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the european space observatory integral has been providing excellent results on x-ray and γ-ray astronomy since its launch in 2004. among the most important results are the spectroscopy and imaging measurements of celestial γ-ray sources, including mapping of 511 kev radiation from galactic plane. however the nature of... | investigation of the galactic center with galacticcenterexplorer (galcenex) |
we describe a creation of the sky maps in 2-5 and 5-10 kev range using public database of observations of x-ray cosmic observatory xmm-newton. considering as an example a search of the dark matter decay line we show how the obtained sky maps can be used for actual astronomical tasks. | creation of the x-ray sky maps and their application for a search of the dark matter decay line |
we observed grb 191221b with the meerkat radio telescope on 21 january 2020 from 20:26 to 21:26 utc (~30 days after the trigger) at a position consistent with the x-ray position reported by beardmore et al. (gcn 26540). we used j0408-6545 as the bandpass and flux calibrator, which was observed for 10 minutes at the sta... | meerkat observation of grb 191221b |
emission from electron-positron annihilation at 511 kev was the first extrasolar gamma-ray line ever detected. despite more than 30 years of theoretical and observational progress, the origin of the positron population has yet to be identified, with potential candidates ranging from microquasars and x-ray binaries to a... | a novel approach to map 511 kev positron annihilation signal in our galaxy |
the flare-excited longitudinal intensity oscillations in hot flaring loops have been recently detected by sdo/aia in 94 and 131 bandpasses. these oscillations show similar physical properties (such as period, decay time, and trigger) as those slow-mode standing waves previously detected by the soho/sumer spectrometer i... | coronal seismology of flare-excited longitudinal slow magnetoacoustic waves in hot coronal loops |
the nasa physics of the cosmos program is a portfolio of space-based investigations for studying fundamental processes in the universe. areas of focus include: probing the physical process of inflation associated with the birth of the universe, studying the nature of the dark energy that dominates the mass-energy of th... | the nasa physics of the cosmos program |
a new soft x-ray (sxr) spectrometer combines proven detector technology demonstrated on the soho solar euv monitor (soho/sem) and sdo euv spectrophotometer (sdo/eve/esp) instruments with novel technology for x-ray optics nanofabrication developed at the lawrence berkeley national laboratory. the new spectrometer will p... | soft x-ray (1-7 nm) solar spectrometer based on novel nanowriter electron-beam nanofabrication technology |
new laboratory measurements of the x-ray emission of ionized iron could help correct spectral models of astrophysical objects. | resolving discrepancies in x-ray astronomy |
we explore the relationship between obscured active galactic nuclei (agns) and their host galaxies, using x-ray data from chandra and nustar observations as well as other deep multiwavelength surveys in the infrared (ir) and optical bands. with nustar observations of four quasars, we have uncovered evidence for extreme... | obscuration of active galactic nuclei and connections to host galaxies |
we present results of recurrence analysis of 46 active galactic nuclei (agn) using light curves from the 70 month catalog of the swift burst alert telescope (bat) in the 14-150 kev band. recent applications of recurrence analysis, an alternative method to fourier analysis, have shown promise in characterizing the abund... | investigating non-linear and stochastic hard x-ray variability of active galactic nuclei |
ngc 4449, a magellanic-type irregular galaxy at a distance of about 4 mpc, contains the most luminous known supernova remnant (snr) in both x-ray and optical bands. its optical spectrum is characterized by broad lines from o, ne, s, ar, and ca, and its size and expansion velocity (6000 km/s) suggest that the unobserved... | the extraordinary supernova remnant in ngc 4449 revisited |
galactic black hole binaries (gbhb) are among the most extreme astrophysical systems in the universe. detailed studies of gbhbs promises insights into some of the most intriguing questions of modern era such as how far the general theory of relativity is valid in strong gravity regime and how does a black hole influenc... | understanding galactic black hole binary systems in the era of astrosat and beyond |
colibrì is a x-ray telescope which is currently in the concept study phase. the main objective of the colibrì mission is to study the structure of accretion flows in the near vicinity of black holes and neutron stars and the study of emission from the surface of neutron stars. with high spectral and time resolution, an... | the colibrì mission: canada's flag-ship x-ray telescope |
coronal heating increases significantly with the strength of the magnetic field. this can be seen in coronal x-ray emission of sunspot active regions, as those are notably brighter than the rest of the corona. fisher et al, using the yohkoh soft x-ray telescope (sxt) found a linear relationship between luminosity and t... | exploration and parameter study of active region luminosity |
following the detection of grb210731a by swift and its x-ray counterpart (troja et al., gcn30568), the 0.6m meerlicht telescope, located at sutherland, south africa obtained a repeating series of 60s images in the q,u,q,g,q,r,q,i,q,z bands. observations began at 2021-07-31, 22:25:54 ut, 5 minutes after the swift detect... | grb 210731a: meerlicht optical afterglow detection |
in order to build our parent sample of galaxies for the local agn survey (lasr), we combine the 2mass redshift survey (2mrs; huchra et al. 2012apjs..199...26h, cat. j/apjs/199/26) with galaxies from the major public astronomical data bases. namely, the lasr-gps is created by querying the 2018 december release of the na... | vizier online data catalog: local agn survey (lasr) i (asmus+, 2020) |
recent discoveries demonstrated that the surface of mars, ceres and other celestial bodies like asteroids and comets are characterized by the presence of ammonium bearing minerals (dalle ore et al., 2018; berg et al., 2016, poch et al., 2020). data collected by new horizon lorri and ralph emphasized the presence of amm... | reflectance spectroscopy of ammonium-bearing minerals: a tool to improve the knowledge of the icy planetary bodies |
telescopes provide us with a chance to see what objects in our universe look like in different kinds of light. by translating the inherently digital data (encoded in the form of ones and zeroes) captured by telescopes into images, astronomers create visual representations that would otherwise be invisible to human visi... | chords of the cosmos: converting data of our universe into sound |
total masses of six quiescent prominences observed from april through june 2011 were estimated using multi-spectral observations (in euv, x-rays, hα, and ca <small>ii</small> h). the method for the total mass estimation is based on the fact that the intensity of the euv solar corona at wavelengths below 912... | is it possible to use the green coronal line instead of x rays to cancel an effect of the coronal emissivity deficit in estimation of the prominence total mass from decrease of the euv-corona intensities? |
as the multi-messenger era begins with detections of gravitational waves with ligo and neutrinos with icecube, the fermi gamma-ray burst monitor provides context observations of gamma-ray transients between 8 kev and 40 mev. fermi gbm has a wide field of view, high uptime, and both in-orbit triggering and high time res... | time domain astronomy with fermi gbm in the multi-messenger era |
this talk will open a special session, "exploring time series data in high energy astrophysics," beginning with a brief survey of emerging software aiming to help astronomers explore and model diverse time series data. we will then describe work from our time series explorer (tse) project, producing new algorithms and ... | time series exploration in python and matlab: unevenly sampled data, parametric modeling, and periodograms |
re-release of pantheon software for zenodo. a useful collection of tools for work with high-energy astrophysical data and time series data in general, with particular focus on data from the rossi x-ray timing explorer. | jmcourt/pantheon: zenodo release |
in contrast to the period following ww i, governmental support for astronomy grew enormously after wwii and during the cold war. in spite of reservations expressed by leading astronomers like harlow shapley at harvard and otto struve at yerkes, tools provided by the military took astronomy into directions neither shapl... | the impacts of military, industrial, and private support on modern astronomy |
looking for a fireworks show this 4th of july? try checking out the distant universe, where powerful jets flung from supermassive black holes slam into their surroundings, lighting up the sky. though these jets are hidden behind shrouds of gas and dust, a new study has now revealed some of these young powerhouses.a gal... | a young population of hidden jets |
chandra was the first facility to detect x-ray light from a neutron star (ns) merger. in this too program we propose to continue chandra's legacy in the nascent field of gw astronomy to identify, monitor, and characterize x-ray emission from compact-object mergers detected during ligo/virgo observing run 4 (o4). our go... | mining the gw+em sky: a community program of cxo/vla observations of compact binary mergers |
galaxy clusters, the largest gravitationally-bound structures in the universe, are composed of 50-1000s of galaxies, hot x-ray emitting gas, and dark matter. they grow in size over time through cluster and group mergers. the merger history of a cluster can be imprinted on the hot gas, known as the intracluster medium (... | radio active galactic nuclei in galaxy clusters: feedback, merger signatures, and cluster tracers |
insight-hxmt is the first chinese x-ray astronomical mission, launched successfully on june 15, 2017, from china's jiuquan satellite launch center. insight-hxmt was designed to have a broad energy coverage in x-rays, from 1-250 kev, with excellent timing and adequate energy resolution at soft x-rays, and the largest ef... | introducing a special collection of papers in the journal of high energy astrophysics on the early results of china's 1st x-ray astronomy satellite: insight-hxmt |
the emissions of volcanic gases over the earth's history have played a major role in changing the chemistry of the terrestrial atmosphere with implications for life development and sustainability (kasting and catling 2003). sedimentary rocks record geological processes that occurred at the interface between water and/o... | geochemical and mineralogical investigations of the bonarelli level (gubbio, italy): evidence of hg anomalies |
spectroscopic images of the sun can provide temperature and velocity information when monitoring and detecting solar flares. solar flares and the associated coronal mass ejections (cmes) can send fast moving charged particles directly into the path of earth and impact space-borne instrumentation and astronauts. strong ... | unfolding overlapping spectral images to determine the plasma velocity during a solar flare |
our discovery of the first x-ray counterpart of a gw event, followed bya long-term multi-wavelength monitoring, provided the first compellingevidence of a r elativistic outflow launched from the merger remnant andseen off-axis. during the next science run, planned to start in early2019, the gw detectors will lead to ro... | observing the gravitational wave sky with xmm-newton |
we use h_ image observed at huairou solar observing station of national astronomical observatories of china and multi-wavelength images observed by atmospheric imaging assembly (aia) onboard the solar dynamics observatory (sdo) to analyze a prominence eruption on 14 october 2012. during the rising phase of the prominen... | multi-wavelength analysis of a helical prominence eruption |
foxsi (which stands for the focusing optics x-ray solar imager) is a sounding rocket payload that has completed three successful flights supported by the low-cost access to space (lcas) program of nasa. foxsi stands out for being the first telescope optimized to use direct focusing to perform imaging spectroscopy of so... | hardware upgrades and science outcomes from the latest flights of the foxsi rocket |
our research group is uniquely positioned to contribute to global pulsar science. we made inputs to the fermi lat's galactic working group objectives via our numerical modelling of gamma-ray light curves and interpretations of pulsar population characteristics in the gev energy band. we have also done work on the expec... | a south african contribution to global pulsar science |
magnetic reconnection has been proposed as a theory for explaining particle acceleration in solar flares. however, previous kinetic simulations of non-relativistic reconnection have not been able to obtain a power-law energy spectrum, which is a key observational feature of particle distribution. here we present result... | the formation of power-law energy spectrum in 3d low-beta magnetic reconnection |
the coronal solar magnetism observatory (cosmo) is proposed to nsf as a mid-scale r-2 facility. the central instrument in the cosmo suite is a 1.5m-aperture large coronagraph (lc) and filtergraph that will obtain daily measurements the coronal magnetic field strength and orientation, velocity, temperature, density and ... | a vis/ir spectropolarmetric filtergraph for the cosmo large coronagraph |
the field of artificial intelligence based image enhancement has been rapidly evolving over the last few years and is able to produce impressive results on non-astronomical images. in this work we present the first application of machine learning based super-resolution (sr) and de-noising (dn) to enhance x-ray images f... | deep learning-based super-resolution and de-noising for xmm-newton images |
taurus hill observatory (tho) [1], observatory code a95, is an amateur observatory located in varkaus, finland. the observatory is maintained by the local astronomical association warkauden kassiopeia. tho research team has observed and measured various stellar objects and phenomena. observatory has mainly focused on e... | taurus hill observatory season 2020/2021 exoplanet review. hat-p-38b (hiisi) and secondary eclipse of the hat-p-32b exoplanet. |
this paper presents a low-noise wide-dynamic-range pixel design for a high-energy particle detector in astronomical applications. a silicon on insulator (soi) based detector is used for the detection of wide energy range of high energy particles (mainly for x-ray). the sensor has a thin layer of soi cmos readout circui... | a low-noise wide-dynamic-range event-driven detector using soi pixel technology for high-energy particle imaging |
increasing observational evidence shows that a non-negligible fraction of the cosmic carbon is locked into macromolecules like polycyclic aromatic hydrocarbons (pahs). interstellar pahs live in extreme environments where there are processed by energetic photons (uv and x-rays) and by ions and electrons accelerated in h... | the importance of being stable: new results about the survival of pahs in extreme astrophysical environments |
onboard chandrayaan-2 orbiter, an x-ray solar monitor (xsm) instrument was flown for the measurement of intensity of solar x-rays within energy band of 1-15 kev. to achieve this, an active filter wheel drive mechanism is used to control the energy of the solar flares falling onto the detector by flipping the filter whe... | design & development of x-ray solar monitor (xsm) filter wheel drive mechanism with self hold down feature for chandrayaan-2 orbiter |
the x-ray telescope (xrt) onboard the hinode satellite has a specially designed wolter type grazing-incidence (gi) optics with a paraboloid-hyperboloid mirror assembly to measure the solar coronal plasma of temperatures up to 10 mk with a resolution of about one arc sec. one of the main purposes of this scientific miss... | detailed calibration of the off-axis optical characteristics for the x-ray telescope onboard hinode |
we request 17 orbits to secure for the first time an uv spectrum of a generic ultraluminous x-ray source (ulx). consisting of an accreting compact object, a neutron star or a black hole, and a non-degenerate donor star, ulxs have highest x-ray luminosities among all types of x-ray binaries. these ultra-high luminositie... | catching wind with the hst: novel uv spectroscopy of a bona fide ultraluminous x-ray source |
the fourth fermi large area telescope (lat) catalog (4fgl) contains 5064 gamma-ray sources detected at high significance, but 26% of them still lack associations at other wavelengths. identifying these unknown gamma-ray sources is one of the major scientific goals in high-energy astronomy. the south pole telescope (spt... | new identifications and multi-wavelength properties of extragalactic fermi gamma-ray sources in the spt-sz survey field |
phosphorous, p, is a key biological element with major roles in replication, information transfer, and metabolism (maciá, 2005). interplanetary dust particles contain ∼0.1% p by weight, and meteoric ablation in the 1 μbar region of a planetary upper atmosphere will inject p, po etc. into the atmosphere. these species w... | phosphorus chemistry in planetary upper atmospheres |
the spectrometer/telescope for imaging x-rays (stix) on board solar orbiter (krucker et al., 2020) uses an indirect imaging system to measure flare location, size and morphology. pairs of tungsten grids create moiré fringes on its coarsely pixelated cdte detectors. images are then reconstructed on the ground, using sop... | the first stix coarse flare locations |
we performed a bayesian analysis which constrains the neutron star mass-radius relation using observations from quiescent low-mass x-ray binaries, photospheric radius expansion x-ray bursters, merger event gw170817, and j0030+0451 from nicer. this observational data set provides tight constraints on mass-radius relatio... | constraints on neutron star masses and radii in this era of multi-messenger astronomy |
under the coordinated national project rti2018-096686-b-c2, the collaboration among research groups at icma(csic-uz), icmab(csic) and ifca(csic-uc)+ucm has developed for the first time in spain an instrumental setup to fabricate transition edge sensors (tes), measure the detected x-ray pulses in the lab and reconstruct... | transition edge sensors devices 'made in spain': from fabrication to photon energy measurements |
we observed grb 210626a detected by fermi gbm (gcn #30323) with 0.7 m growth-india telescope (git). the grb was also detected by swift/bat-guano (gcn #30325) and later on, swift-xrt detected x-ray afterglow candidate (gcn #30329). we obtained exposures in the r' filter. we did not detect any new source in our stacked i... | grb 210626a: git optical upper limit |
the first detection and deep follow-up of a galactic fast radio burst (frb) phenomenon were reported in three papers published in the journal nature in november 2020. interestingly, this frb is accompanied by a x-ray burst. the observations from multiple space and ground-based telescopes were combined to accomplish thi... | a commentary of "consistency radio bursts in the milky way": 10 remarkable discoveries from 2020 in nature |
x-ray imaging spectroscopy mission (xrism) is the next japanese x-ray astronomical satellite to be launched in 2021 japanese fiscal year. we are developing one of the xrism instruments "xtend", which is an x-ray ccd camera combined with an x-ray telescope, and achieves the wide field of view of 38′ × 38′ in 0.4-13 kev.... | screening and selection of xrism/xtend flight model ccd |
astrosat is india's first mission dedicated to space-based astronomy and carries a complement of instruments sensitive over a wide spectral region covering visible, ultraviolet, soft x-ray and hard x-ray bands. the spacecraft platform provides the required stability, pointing, power, thermal control, and interface requ... | innovations in the aocs of astrosat spacecraft |
astronomical observations of distant quasars may be important to test models for quantum gravity, which posit planck-scale spatial uncertainties (`spacetime foam') that would produce phase fluctuations in the wavefront of radiation emitted by a source, which may accumulate over large path lengths. we show explicitly ho... | new constraints on quantum foam models from x-ray and gamma-ray observations of distant quasars |
earth's climate during the neogene period changed in several steps from a planet with unipolar ice sheets to today's bipolar configuration. yet, time-continuous and well-preserved sedimentary archives from this time interval are scarce. this is especially true for those records that can be used for tracing the role of ... | astronomically-paced changes in paleoproductivity, winnowing, and mineral flux over broken ridge (indian ocean) since the early miocene |
the x-ray astronomical telescopes in use today, such as chandra and xmm-newton, use x-ray grating spectrometers to probe the high energy physics of the universe. these instruments typically use reflective optics for focussing onto gratings that disperse incident x-rays across a detector, often a charge-coupled device (... | the simulated spectrum of the ogre x-ray em-ccd camera system |
we continued the observation of x-ray source (#4) by swift-xrt too observations (m. perri et al. gcn # 31013), a candidate for the afterglow of fermi gbm grb 211024a (gcn 30962), a. tohuvavohu et al., (gcn #31006), with 0.7m growth-india telescope (git). we obtained multiple exposures of 300 sec each in the g', r' and ... | grb 211024a: swift-xrt source 4 is not an afterglow. |
gamma-400 (gamma astronomical multifunctional modular apparatus) will be the new generation satellite gamma-observatory. the gamma-ray telescope gamma-400 consists of anticoincidence system (top and lateral sections - actop and aclat), the converter-tracker (c), time-of-flight system (two sections s1 and s2), position-... | additional aperture detectors of gamma-telescope gamma-400 calibrations on synchrotron “pakhra”: possibility of temporal profiles fractal analysis |
understanding the chemistry of the interstellar medium (ism) is fundamental for the comprehension of the galaxy evolution. some of the refractory interstellar elements, such as si, mg, o and fe, are known to be locked up into dust grains. iron is known to be highly depleted from the gas phase into solids, but the exact... | oxygen and iron in interstellar dust: an x-ray view |
the jules horowitz reactor (jhr) is a european material testing reactor (mtr) under construction at the cea cadarache centre. it will be dedicated to material and fuel irradiation tests, as well as to the production of medical isotopes. gamma and x-ray benches will be implemented in the reactor pool (rer), the irradiat... | non-destructive examination development for the jhr material testing reactor |
fast radio bursts (frbs) are millisecond duration pulses of radio emission that are bright enough to be seen from other galaxies. the nature of the objects that produce fast radio bursts has captivated the interest of astronomers since their discovery in 2007. the durations and energetics of frbs imply a compact, highl... | the progenitors of fast radio bursts |
at the university of chicago, i run a vigorous research program in astronomy involving undergraduate students. i have had over 35 students work with me, about half of whom were female and minority students. some students have started research projects early in their first year itself. i do not ask undergraduate student... | facilitating high-level undergraduate research in astronomy via individual student projects |
we present an extensive statistical study of all 29 chandra high resolution camera (hrc-i) observations, covering ∼ 20 years worth of data from 18th december 2000 to 8th september 2019. eight of these observations were pre-juno and 21 while juno was exploring the jovian system providing in situ context. the first spati... | characteristics of jupiter's x-ray auroral hot spot emissions using chandra |
robust non-local spin voltage signals have been demonstrated experimentally in monolayer graphene deposited on the (0001) surface of the antiferromagnetic chromium oxide (cr2o3). the measured non-local voltage shows fluctuations at a wide range of energies reminiscent of universal conductance fluctuations but with larg... | non local transport in graphene/chromia |
over the course of two solar cycles, rhessi has examined high-energy processes in flares via high-resolution spectroscopy and imaging of soft and hard x-rays (hxrs). the detected x-rays are the thermal and nonthermal bremsstrahlung from heated coronal plasma and from accelerated electrons, respectively, making them uni... | focusing solar hard x-rays: expected results from a foxsi spacecraft |
the outskirts of galaxy clusters have low surface brightness compared to the x-ray background, making accurate background subtraction particularly important for analyzing cluster spectra out to and beyond the virial radius. we analyze the thermodynamic properties of the intracluster medium (icm) of abell 133 and assess... | systematic uncertainties in characterizing cluster outskirts: the case of abell 133 |
ep satellite is a scientific exploration satellite for time-domain astronomy and high-energy astrophysics, its function is to carry out high-energy transitory celestial body survey with the highest sensitivity in the soft x-ray band. ep will be equipped with two groups of x-rays focusing mirrors (each group contains 54... | development of wolter-i x-ray focusing mirrors measurement device |
the results of long-term mesoscale observations in the microwave range are reviewed. the rationale for the resumption of observations at the havana radio astronomy station is justified. domestic observations at a wavelength of λ5 cm have a long observation interval and can effectively complement the global series of ob... | observation of the radio radiation flux of the sun and flares at a wavelength of 5 cm |
the goal of this project is to fly two suborbital rockets for x-ray astronomical observations. the first flight will use an existing payload and replace the gem detectors with state-of-the-art hybrid cmos detectors, a key technology for future nasa missions. concurrently, this payload will be the first science flight f... | x-ray rocket payloads for key technologies and core science |
the key, central objectives of the proposed time series explorer project are to develop an organized collection of software tools for analysis of time series data in current and future nasa astrophysics data archives, and to make the tools available in two ways: as a library (the time series toolbox) that individual sc... | time series explorer |
the wisconsin/gsfc x-ray quantum calorimeter (xqc) is an astronomical x-ray sounding rocket payload which uses a micro-calorimeter array to detect low (less than1kev) x-rays. three different devices were evaluated to upgrade xqc's data collection and recording system. the system takes incoming data from xqc's pixel sen... | data collection and recording on the wisconsin/gsfc x-ray quantum calorimeter |
there are four decades of broadband soft x-ray (sxr) measurements, but these measurements cannot directly quantify the varying contributions of emission lines (bound-bound) amongst the thermal radiative recombination (free-bound) and thermal and non-thermal bremsstrahlung (free-free) continua. the miniature x-ray solar... | improving solar soft x-ray (sxr) irradiance results from broadband photometers with new sxr spectral measurements from a cubesat |
the oh^+ ion is an important species in the interstellar medium. it has been used to infer the cosmic ray ionization rate and is an important intermediate for generation of more complex astrochemical species. oh^+ observations are typically performed in the sub-millimeter and near-uv ranges, and rely on laboratory spec... | fourier transform spectroscopy of the a^3π -x^3σ^- transition of oh^+ |
high-angular-resolution cosmic microwave background experiments provide a unique opportunity to conduct a survey of time-variable sources at millimeter wavelengths, a population which has primarily been understood through follow-up measurements of detections in other bands. here we report the first results of an astron... | detection of stellar flares at millimeter wavelengths with spt-3g |
scientific progress in understanding the universe requires data across the electromagnetic spectrum. to address the cutting edge scientific problems of the coming decades, we need x-ray data with sub-arcsecond resolution. to use such precise angular resolution effectively and efficiently, large collecting areas are nec... | adjustable x-ray optics |
maxi (monitor of all-sky x-ray image) is an astronomical mission onboard the international space station. it started observations in august 2009. the gas slit camera of maxi is sensitive to x-rays in the energy range 2-30 kev. most of the sky is scanned every 90 min with the orbital revolution of the iss. with this unb... | x-ray transients observed with maxi |
marxs (multi-architecture-raytrace-xraymission-simulator) is a toolsuite to simulate x-ray observatories. it is primarily aimed at astronomical x-ray satellites and sounding rocket payloads, but can be used to ray-trace experiments in the laboratory as well. marxs performs polarization monte-carlo ray-trace simulations... | chandra-marx/marxs: v1.1 |
x-ray astronomy entered a new era with the advent of high-spectral resolution grating spectrometers aboard the chandra and xmm-newton x-ray observatories and, very recently, with the launch of the high-resolution calorimeter (sxs) aboard the hitomi mission. the ability to perform spectrally resolved observations has ne... | laboratory astrophysics in support of high-resolution x-ray astronomy |
the megs-a spectroscopy of the sun as a star has produced a greatdeal of interesting solar physics, but without much exploitationyet of its doppler capabilities (see chamberlin, 2016 for details).in this presentation we examine the he ii 304 line specifically andin specifically on the database of x-class flares from me... | eve doppler signatures in x-class flares |
the small magellanic cloud putative b star suggested to be the optical counterpart of the transient or recurrent xmm supersoft x-ray source xmmu j010147.5-715550 (sturm et al., 2012, a & a 57, 76) was observed by us on september 7th, 2016 (jd 2457640.5) with the southern african large telescope (salt) at the south ... | xmmu j010147.5-715550, another luminous supersoft x-ray source with a be optical counterpart |
beginning with the einstein observatory in 1978, continuing with rosat in the 1990's and currently the chandra x-ray observatory, high angular resolution focusing telescopes have been the premier x-ray astronomy instruments of their time. however, as they have acquired larger area and improved angular resolution they h... | the future of high angular resolution x-ray optics for astronomy (conference presentation) |
we present the nustar sensitivity to quiet sun (qs) transient events, which have been seen in wavelengths from uv to soft x-rays. although not optimized for solar observations, nustar can observe x-ray emission from the sun with unprecedented sensitivity in the hard x-ray range; this is crucial for detecting individual... | the nustar sensitivity to quiet-sun transient events |
spherex, a mission in nasa's small explorer (smex) program that was selected for phase a study in july 2015, will perform an all-sky near-infrared spectral survey between 0.75 - 4.8 microns, reaching 19th mag (5sigma) in narrow r=40 filters. the key science topics of the spherex team are: (a) primordial non-gaussianity... | spherex: science opportunities for the astronomical community |
the crab nebula, one of the most important and best studied astronomical objects, often considered to be a "standard candle" reference source, is now known to be variable, with flares above 100 mev on 1-day timescales and variability up to ~10% on timescales of ~1 year below 100 kev. these results motivate a search for... | when a standard candle flickers: gamma-ray flares and hard x-ray variations in the crab nebula since 1991 |
many astrophysical plasmas are so hot and diffuse that the collisional mean free path is larger than the system size. perhaps the best examples of such systems are lowluminosity accretion flows onto black holes such as sgr a* at the center of our own galaxy, or m87 in the virgo cluster. to date, theoretical models of t... | instability, turbulence, and enhanced transport in collisionless black-hole accretion flows |
it is generally believed that a 1+1d chiral fermion state can not exist by itself on lattice. the obstruction to such a lattice realization is originated from the quantum anomalies of chiral fermion in quantum field theory. it has been recognized that such an anomalous state have a topologically nontrivial bulk. for ex... | a 1d realization of lattice chiral fermions with a non-hermitian hamiltonian |
promising qubit technologies couple to electromagnetic waves with frequencies that span five orders of magnitude. for example, superconducting microwave circuits and trapped atoms couple to microwave and optical transitions, respectively. transduction of quantum information between these disparate frequencies is theref... | towards efficient electro-optic transduction in thin film lithium niobate |
tidal disruption events (tdes) are a common feature between active and quiescent galactic nuclei; the study of these events is a very useful tool to probe phenomena that relate to the formation of an accretion disc or a jet. also, the accretion rate at the beginning of the tidal flare is expected to be significantly su... | on the likelihood of gravitational wave emission during the tidal disruption of stars by super massive black holes |
we present imaging spectroscopy of the sun with the nustar hard x-ray (hxr) telescope, an astrophysics mission that uses focusing optics to directly image x-rays between ~2-80 kev. although not optimized for solar observations, nustar's high sensitivity can probe previously inaccessible x-ray emission from the sun - cr... | nustar x-ray observations of small flares and non-flaring active regions |
transition-edge sensor (tes) microcalorimeters have growing applications in x-ray and gamma-ray astronomy due to their high energy resolution and fast rates of time-stamping of individual photons. we are testing and optimizing a 32-pixels sledgehammer (spectrometer to leverage extensive development of gamma-ray tess fo... | transition-edge sensor microcalorimeter detectors for future x-ray and gamma-ray mission |
during a solar flare the rapid release of magnetic energy drives extremely efficient particle acceleration through a mechanism which remains largely unknown. hard x-ray observations are one of the most direct signatures of flare accelerated energetic electrons at and near the acceleration site, and x-ray spectra can pr... | the micro solar flare apparatus (misolfa) |
whats the mechanism behind millisecond-duration bursts of radio energy coming from outer space? a team of astronomers performed a systematic search of optical transients to see if they could match one radio burst with another object, which would help constrain where these bursts come from.fantastic, radiant, bafflingfa... | a possible optical counterpart to frb 180916b? |
active galactic nuclei (agns) are among the most energetic objects in the universe. these galaxies that are dominated in part or even throughout the electromagnetic spectrum by emission from their central, compact region. agns are extensively studied by multi-wavelength observations. in the standard picture, the main d... | a radio view of high-energy emitting agns |
on 28 march 2011, a tidal disruption candidate associated with the suppermassive black hole, swift j164449+573451 (hereafter swift j1644+57), was discovered. a tidal disruption is an astronomical phenomenon in which a black hole destroys a star passing too near the black hole, emitting bright flares in the ultraviolet ... | suzaku observation of the tidal disruption event on swift j1644+57 |
the first association of a short gamma-ray burst (sgrb) with a gravitational wave (gw) event proved that binary neutron star mergers (bns) are the progenitors of at least a some sgrbs and propelled astronomy into a new multi-messenger era. through this single detection, the multi-messenger community received new insigh... | development of instrumentation and methodology to expand our view of gamma-ray bursts: the calibration of the burstcube instrument and a methodology for measuring spectral lags in gamma-ray bursts with multiple emission components |
the astronomical silicate (astrosilicate) was constructed to reproduce features observed in the interstellar medium (ism) and has been used with relative success to reproduce features observed in the spectral energy distributions of stars with circumstellar disks containing thermally emitting dust. while astrosilicates... | optical constants of minerals for circumstellar disk modeling |
the juno mission has promoted and coordinated a network of earth-based observations, including both space- and ground-based facilities, to extend and enhance observations made by the juno mission. the spectral region and timeline of all of these observations are summarized in the web site: https://www.missionjuno.swri.... | results from joint observations of jupiter's atmosphere by juno and a network of earth-based observing stations |
for a study of the imf and the star-formation history of the young open cluster ic 1805, we obtained deep wide-field vri and hα images of ic 1805 using the cfh12k mosaic ccd camera of the cfht on 2002 january 6 and 7. we also observed several regions in ic 1805, for a study of the reddening and massive star content, us... | vizier online data catalog: optical & spitzer photometry in ic 1805 (sung+, 2017) |
the distance of a black hole x-ray binary (xrb) system is of high significance because it helps us in determining the physical parameters from observables, such as velocity from proper motion, physical separation from angular separation, and luminosity from flux. in many cases, the distance to a source can not be deter... | hi absorption distances to black hole x-ray binary candidates |
distance measures are of critical importance to all areas of astronomy from cosmology to stellar evolution. geometric distance measures are by far the most accurate, but are frequently limited to nearby objects. recent significant disagreement between optical and radio measures of hubble's constant may indicate that th... | geometric distances to the magellanic clouds and grb prompt x-ray emission study via dust scattering |
discovery of gw150914, lvt151012, and gw151226, the first ligo gravitational wave candidates and the first unambiguous binary black hole mergers, represents one of the most exciting advances in physics in decades. ligo constrained the masses and emitted energies in these events to exquisite precision, but at 90% confid... | bringing gravitational wave astronomy to light: chandra x-ray localization of ligo-virgo gw sources |
sixty five x-ray observations for the 22 star formation in nearby clouds (sfincs) star-forming regions (sfrs) (see tables 1 and 2), made with the imaging array on the advanced ccd imaging spectrometer (acis), were pulled from the chandra archive (spanning 2000 jan to 2015 apr; see table 2). our final chandra-acis catal... | vizier online data catalog: sfincs: x-ray, ir and membership catalogs (getman+, 2017) |
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