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we present an mhd simulation of the initiation of the coronal mass ejection (cme) on 13 december 2006 in the emerging δ-sunspot active region noaa 10930. we have improved upon a previous simulation by fan (2016) in the following ways: (1) incorporate an ambient solar wind instead of using a static potential magnetic fi... | mhd simulation of the 13 december 2006 eruptive flare of ar10930 |
svom (space-based multi-band astronomical variable objects monitor) is a mission developed within a sino-french cooperation context and dedicated to the detection, localization and study of gamma ray bursts (grbs) and other high-energy transient phenomena. four instruments, operating in different wavelengths, are imple... | results of the development of the mxt x-ray telescope for the svom mission |
with upcoming ground-based and the next generation of space-based telescopes, the astronomy research community is working with an ever increasing volume of observations, multidimensional data cubes, and sophisticated statistical techniques for getting the most out of a dataset. i will speak from my experience in the as... | the role of open source software in interpreting astronomical datasets |
along with the "butterfly diagram" of sunspots, combined observational studies of ephemeral active regions, x-ray and euv brightpoints, plage, filaments, facule and prominences demonstrate a pattern, which is known as the extended solar cycle (esc). this pattern indicates the wings of the sunspot butterfly could be ext... | mhd of double-bands representing extended solar cycle |
galaxy clusters are the largest gravitationally bound astronomical bodies in the universe, and they sit at the unique junction between cosmology and astrophysics. one of the recent advances is to use the sunyaev zel'dovich (sz) effect to detect clusters in large area surveys, but these detections require an independent... | analyzing sunyaev zel'dovich galaxy cluster catalogs and the stand out cluster merger act-cl j0034.4+0225 |
on behalf of the eurasian astronomical society, i would like to express my warmest feelings and congratulations to professor nikolai g. bochkarev, editor-in-chief of astronomical and astrophysical transactions on the occasion of his 75th birthday on may 19, 2022. professor bochkarev (phd, dsc) is a scientist in the fie... | nikolai g. bochkarev is 75 |
the impulsive phase rapid energetic solar spectrometer (impress) is an nsf-funded 3u cubesat in development via a collaboration between the university of minnesota, montana state university, the university of california, santa cruz, and the southwest research institute. the mission's primary goal is to measure subsecon... | the impulsive phase rapid energetic solar spectrometer (impress): a time focused x-ray cubesat |
we present surveys and related studies of active galaxies carried out at the byurakan astrophysical observatory (bao). this was one of the main research subjects at bao during many years, since mid-1950s, when viktor ambartsumian suggested the hypothesis of the activity of the galactic nuclei. a number of surveys and s... | surveys for active galaxies: discovery and studies |
cosmological simulations aim to self-consistently model the physics that shapes the distribution of baryons in our universe. galaxy mergers and feedback from supermassive black holes are some of the most violent physical processes in astrophysics, and they leave a major imprint on the interstellar and intracluster medi... | computational modeling of the baryon content of galaxies and clusters in cosmological simulations |
x-ray surveys are an effective way to study growing supermassive black holes (smbhs) in galaxy centers, as actively accreting smbhs manifest themselves as active galactic nuclei (agn) that can be observed in the x-ray in most cases. through studying agns in x-ray survey fields that have extensive multiwavelength data c... | active galactic nuclei studies in cosmic x-ray survey fields |
since the beginning of this decade, we have been enjoying a major transition in solar radio astronomy as it evolves from imaging at a few discrete frequencies to true imaging spectroscopy over a wide frequency range. in this talk, i will review some recent advances based on the use of broadband radio imaging spectrosco... | recent advances in radio imaging spectroscopy for studying high-energy processes on the sun |
to study the flare energetic and energy partition in flare-cme events, we investigate the scaling relationships between several physical parameters during ~40 flare-cme events. we measured the total reconnection fluxes by summing up the photospheric magnetic fluxes swept by spreading flare ribbons. the peak of goes x-r... | a statstical study of plasma energetics in flare-cme events |
the fermi large area telescope (lat) observations of the active sun provide the largest sample of detected solar flares with emission greater than 30 mev to date. these include detections of impulsive and hours-long sustained emission coincident with goes x-ray flares as well as very fast coronal mass ejections (cme). ... | high-energy observations of solar flares during solar cycle 24th with the fermi large area telescope |
it has been firmly demonstrated that direct-focusing instruments can transform the way high-energy x-rays from astronomical objects, including the sun, are measured. the nustar spacecraft has increased the sensitivity to faint astrophysical sources by 100 times as compared with previous, indirect, imagers. the first th... | the foxsi-4 sounding rocket: high resolution focused x-ray observations of the sun |
application of cubesats in astronomical observations has been getting more and more mature in recent years. here we report a concept study of a small compton polarimeter to fly on a cubesat for observing polarization of soft gamma-rays from a black-hole x-ray binary, cygnus x-1. polarization states provide very useful ... | concept study of a small compton polarimeter to fly on a cubesat |
i will give updates on the x ray sig and discuss them with the community. please refer to the physics of the cosmos page for additional details [https://pcos.gsfc.nasa.gov/physpag/meetings/aps_2021/aps2021-agenda.php#xrsig] | introduction to xrsig and highlights in x-ray astronomy |
it has long been recognized that the energy source for major solar flares and coronal mass ejections (cmes) is the solar magnetic field within active regions. specifically, it is believed to be the release of the free magnetic energy (energy above the potential field state) stored in the field prior to eruption. for es... | partially open fields and the energy of solar eruptions |
large-area, low-power, position-sensitive silicon drift detectors are an enabling technology for multiple instrument and mission concepts that address high priority recommendations of astro2020, including an x-ray probe and time domain and multimessenger (tdamm) astrophysics. in italy, infn and inaf have developed sili... | a large area silicon drift detector for x-rays |
time-domain astrophysical objects such as supernovae and gamma-ray bursts are central to compact object formation, heavy element creation, and multi-messenger astronomy. they are strongly associated with many areas of astrophysics. because of this association, observational data of these objects have mushroomed over th... | uv and x-ray observations of shock breakout |
high-energy observations of non-thermal diffuse emission star-forming galaxies provide an excellent opportunity to study cosmic-ray physics in a variety of interstellar environments. recent advances in gamma- ray astronomy in the gev and tev band have resulted in the first detections of non-agn galaxies outside of the ... | probing cosmic-ray physics in starburst galaxies with future high-energy missions |
we have generated a catalog of young stellar objects (ysos) in the star forming region ngc 7538 using ha and x-ray data. the spatial distribution of ysos along with mir, radio and co emission are used to study the star formation process in the region. our analysis shows that the 03v type high mass star 'irs 6' might ha... | riggered star-formation in the ngc 7538 h ii region |
charge-coupled devices (ccds) have been the detector of choice for all x-ray astronomy missions of the past 20 years. i discuss the operational principles of ccds used in the x-ray energy band and review ccd instruments on a variety of astrophysics and heliophysics missions. | x-ray charge-coupled devices |
we present first results of a study of rotation parameters of the tornado-type promi- nences using hα line spectra and filtergrams. the prominences of the tornado-type were observed by ground-based spectrographs mfs and hsfa 2 in the ondrejov observatory (astronomical institute of as cr) from 2000 to 2017. the analysis... | on the role of preflares in tornado-type prominences |
solar coronal jets are magnetically channeled narrow eruptions often observed in the solar atmosphere, typically in euv and x-ray emission, and occurring in various solar environments including active regions and coronal holes. their driving mechanism is still under discussion, but facts that we know about jets include... | a series of streamer-puff cmes driven by solar homologous jets |
the utility of an astronomical x-ray telescope, like that of a telescope of any other band, is largely determined by its angular resolution, photon collecting area, field of view, and energy bandwidth. current and past x-ray telescopes, such as chandra, xmm-newton, suzaku, and nustar, have optimized for one or more of ... | silicon meta-shell x-ray optics for astronomy |
the magnetic field configuration of coronal mass ejections (cmes) as they leave the lower corona can be broadly decomposed into two components. one is the core field that is involved in the initiation of the eruption and the other is the field surrounding the core that is added to the core during the flare reconnection... | the origin of core magnetic structures in coronal mass ejections: observational findings |
nasa has launched a long and storied series of ambitious strategic astrophysics missions, such as the hubble space telescope, compton gamma ray observatory, chandra x-ray observatory, and spitzer space telescope, with the recently launched james webb space telescope set to join their ranks in producing incomparable sci... | nasa strategic astrophysics technology investments: a decade of benefits, outlook informed by the 2020 decadal survey |
neutron stars in binary systems can undergo periods of accretion (outburst), where in- falling material heats the crust of the star out of thermal equilibrium with the core. when accretion stops (quiescence), we can directly observe the thermal relaxation of the crust. crustal cooling of accretion-heated neutron stars ... | crustal cooling in the neutron star low-mass x-ray binary ks 1731-260 |
during the decline phase of solar cycle 24(sc-24), releases of x-class flare possessing high energetic particles. this flare event was more intense than that occurred during the main peak of this cycle. additional eruptive x-class flares were later released during the year 2014and 2015. the aim of this work is to forec... | x-class flares released during the decline phase of the sc- 24 |
x-ray pulsar navigation has attracted extensive attentions from academy and engineering domains. the navigation accuracy is can be enhanced through design of x-ray mirrors to focus x-rays to a small detector. the wolter-i optics, originally proposed based on a paraboloid mirror and a hyperboloid mirror for x-ray imagin... | design and development of grazing incidence x-ray mirrors |
coronal jets, routinely observed by multiple instruments at multiple wavelengths, provide a unique opportunity to understand the relationships between magnetic field topology, reconnection, and solar wind heating and acceleration. we simulate coronal jets with the alfvén wave solar model (awsom) [van der holst (2014)] ... | dynamics of polar jets from the chromosphere to the corona: mass, momentum and energy transfer |
ammonium minerals have been proposed to be present in variable percentage on icy planetary bodies such as enceladus, ceres, pluto and its satellites and their presence is evident also in others celestial bodies. the presence of these compounds is related to the raise of ammonium (nh4+) salts from the interior of the ic... | vis-nir analysis at low temperature and different grain size of ammonium bearing minerals: a tool to improve the knowledge of icy planetary bodies surface. |
we describe radio observations of the gamma-ray pulsar j1836+5925. observations were carried out on the pushchino radio astronomical observatory at the frequency of 111 mhz using the large phased array of the lebedev physical institute. this telescope is one of the most sensitive instruments in the meter wavelengths in... | observations of the gamma-ray pulsar j1836+5925 at 111 mhz |
scintillation detectors have been used for detecting x-rays and γ-rays for more than 60 years. their ease of fabrication in a variety of shapes and sizes, their relatively low cost, their ease of use, and their reliability have made them an invaluable component for a wide variety of high energy astrophysics experiments... | scintillation detectors for x-ray and γ-ray astronomy |
how solar and stellar atmospheres are heated to millions of degrees is a fundamental problem in astrophysics. the parker nanoflare model, in which the topological complexity created by turbulent photospheric motions is dissipated by magnetic reconnection, is perhaps the most widely studied theory of coronal heating. al... | solar soft x-ray spectral measurements and the temperature structure of active regions and flares |
cepheids are pulsating variable stars, meaning that their periodic changes in brightness are associated with changes in physical size. the wavelengths at which cepheids emit radiation also vary as the stars pulsate. so whats happening in the x-ray when it comes to cepheids?classical cepheids and modern observationsx-ra... | seeing cepheids in the x-ray |
evidence of cooling between coronal loops that appear in x-ray images and those that appear in euv loops is scarce. in fact it is widely accepted that `cool and warm' (1-2.5 mk) euv loops and `hot' x-ray loops are two different species. observationally each group has distinct intensities, densities, and lifetimes. thus... | possible evidence of coronal loops cooling from x-ray to euv images |
during chandra ao9, ao12, ao13, ao15, ao17 and ao20 we thought we completed the xray coverage of extragalactic radio sources in the revised third cambridge catalog (3cr). however, while carrying out our 3cr chandra snapshot survey, we found that there are still 25 3cr sources unidentified, lacking optical counterparts ... | xraying the unknown 3cr extragalactic sky |
simulations of the soft x-ray emission from the magnetosheath are required in order to determine the extent to which proposed missions will be able to determine the location of the magnetopause and bowshock. simulating the soft x-ray images of the magnetosheath requires a wide array of models (see talks by collado-vega... | simulating soft x-ray images of the magnetosheath |
the dynamic radio sky is full of fast radio transients that produce emission on timescales ranging from nanoseconds to seconds. the two classes of fast radio transients studied in this thesis are pulsars and fast radio bursts (frbs). pulsars are highly magnetized, rotating neutron stars that produce pulses of electroma... | hunting for fast radio transients in the local universe and pulsars toward the center of the milky way galaxy |
the marshall grazing incidence x-ray spectrometer (magixs) is a nasa sounding rocket instrument designed to observe soft x-ray emissions at 0.5 - 2.0 kev energies (24 - 6 å) from a solar active region. magixs will, for the first time, obtain spatially resolved spectra of high-temperature, low-emission plasma within an ... | status of mirror development for the marshall grazing incidence x-ray spectrometer (magixs) |
the cor and pcos program offices (pos) reside at the nasa goddard space flight center (gsfc), serving as the nasa astrophysics division's implementation arm for matters relating to the two programs. one aspect of the po's activities is managing the cor and pcos strategic astrophysics technology (sat) program, helping m... | nasa astrophysics funds strategic technology development |
the ligo-virgo scientific collaboration recently reported the first two direct detections of gravitational wave (gw) signals and demonstrated that these events (gw150914 and gw151226) were produced by the inspiral and coalescence of binary black holes (bhbhs). this breakthrough marks the beginning of the era of gw astr... | compact binary mergers in general relativity |
the sun's atmosphere increases in temperature from 6000 degrees at the surface to over a million degrees at heights of a few thousand kilometers. this surprising temperature increase is still an active area of scientific study, but is generally thought to be driven by the dynamics of the sun's magnetic field. the combi... | the sun: our own backyard plasma laboratory |
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 recent discovery of serendipitous x-ray flux with no radio counterpart surrounding the quasar b3 0727+409 (simionescu et al. 2018), as well as the identification of two more of these sources (schwartz et al. 2020), has raised countless questions in the field of x-ray astronomy. despite all the discoveries made by t... | a meta-survey to identify high-redshift quasars with extended and/or serendipitous x-ray emission |
rv tauri variables are luminous pulsating supergiant stars (~10^3 lsun) with pulsation periods between ~20--150 days and extend the period--luminosity relation of type ii classical cepheids. in addition to pulsational variability, a subset of rv tauri stars (the rvb-type) exhibits a longer periodic modulation in bright... | stellar evolution at the crossroads: resolving the nature of rv tauri variable systems using unprecedented observations from the kepler and xmm-newton space telescopes |
active galactic nuclei (agn) are a laboratory for understanding the growth of supermassive black holes through accretion and their impact on galaxy evolution. nasa surveys have been foundational in discovering diverse examples of agn, via emission from infrared to gamma-ray wavelengths. the characteristics of agn in an... | a multiwavelength study of agn evolution from z=7 to z=0 with a database of 7.5 million sources. |
we investigate the densities and temperatures of erupting prominences associated with coronal mass ejections and x-ray flares. several events observed in euv by aia/sdo show that the absorption features of prominences/filaments change to emission features during their eruptions, which indicates the heating of the erupt... | study on the temperature and density of erupting prominences associated with coronal mass ejections |
coronal jets are transient, collimated plasma ejections that occur predominantly in coronal holes and are observed in euv, soft x-ray, and occasionally in white-light coronagraphs. while these intriguing phenomena have been studied and modeled for more than two decades, the details of their formation mechanism(s) are n... | thermodynamic mhd simulations of jets in the solar corona and inner heliosphere |
we requested follow-up time for the amon alert nuem230927a (gcn 34776). the follow-up looks for any x-ray source inside the 90% region of the amon alert: ra (j2000): 331.92 deg dec (j2000): 12.44 deg location uncertainty (90% containment): 0.24 deg (statistical only). we used the available software in www.swift.ac.uk s... | nuem-230927a: swift-xrt follow-up |
there are two well established populations of black holes: (i) stellar-mass black holes with masses in the range 5 to 30 solar masses, many millions of which are present in each galaxy in the universe, and (ii) supermassive black holes with masses in the range millions to billions of solar masses, which reside in the n... | a global spectral study of stellar-mass black holes with unprecedented sensitivity |
this thesis addresses the distributions of baryonic matter on three scales: the outskirts of the gas and galaxy profiles in galaxy clusters, the clustering of galaxies of galaxies on large scales and its relation to the underlying matter distribution, and the extremes of the galaxy distribution: the connections between... | distributions of gas and galaxies from galaxy clusters to larger scales |
micrometeoroids are micron-sized dust particles orbiting at hypervelocities of a few tens of kilometers per second. impacts on sensitive x-ray astronomical devices in space can degrade their performance and even lead to fatal loss of at least parts of their functionality, like in the case of two ccds of the epic mos1 c... | srg/erosita micrometeoroid hits and effects |
astronomical x-ray diffraction gratings are a key technology under development for current and future nasa missions. x-ray reflection gratings developed at penn state university have recently demonstrated both leading diffraction efficiency and high spectral resolving power. however, recent yields are the results of di... | an update on x-ray reflection gratings for space missions |
positions and redshifts of the fields with spectroscopic follow-up with the lbt. the astrometry is based on the sdss. we give redshifts based on lbt/mods observations. optical magnitudes were measured using sextractor's iso-mag on lbt/lbc imaging in the sloan-r and sloan-z filters. the errors for the magnitudes are giv... | vizier online data catalog: distant clusters of galaxies in the 2xmm/sdss (rabitz+, 2017) |
with the advent of the nanosat/cubesat revolution, new opportunities have appeared to develop and launch small ($\sim$ 1000 cm$^3$), low-cost ($\sim$ us\$ 1m) experiments in space in very short timeframes ($\sim$ 2 years). in the field of high-energy astrophysics, in particular, it is a considerable challenge to design... | the lecx experiment on the nanomirax satellite |
a novel computational model for describing energetic electrons produced by magnetic reconnection in macroscale systems is developed and explored. it has long been known that magnetic reconnection in the solar corona produces a power law for high energy electrons (lin & hudson 1971; emslie et al. 2004; emslie et al.... | a computational model for exploring particle acceleration during macroscale magnetic reconnection |
professor riccardo giacconi died on 9th december 2018; he was 87. he was an outstanding, extraordinary scientist - a pioneer and founder of x-ray astronomy and a nobel laureate. professor giacconi had a major infl uence on modern astronomy and astrophysics and through his leadership, energy and contribution, ensured th... | riccardo giacconi (1931-2018) |
a germanium charge-coupled device (ccd) offers all of the advantages of silicon ccds - notably excellent uniformity, high energy resolution, and noiseless on-chip charge summation - but covers an even broader spectral range, extending into the hard x-ray band. mit lincoln laboratory has been developing germanium ccds f... | germanium charge-coupled devices for hard x-ray astronomy |
many scientific theories have been proposed in the hopes of better understanding the coronal heating problem. this project largely focuses on the theory that the solar corona is heated by alfvén wave turbulence from solar coronal loops. these waves are thought to be propagated by motion at the foot points of the corona... | coronal heating consequences from alfvén wave turbulence in solar coronal loops |
particle acceleration by magnetic reconnection during solar flares is an important unsolved problem. a major difficulty for resolving this problem is to adequately describe particle acceleration and transport in and around the solar flare reconnection region. built on results and analysis on plasma kinetic simulations,... | large-scale electron acceleration by magnetic reconnection during solar flares |
our ultimate goal is to obtain at least an exploratory chandra observation for the entire extragalactic 3cr catalog. to achieve this aim we worked out in redshift with modest proposals each year. the first segments were completed in ao9 and ao12, obtaining all previously unobserved by chandra 3cr sources with z<0.3.... | completing the chandra extragalactic 3cr survey |
joint detections between gravitational waves and gamma-ray bursts (grbs) enables multi-messenger science and allows for constraints on the neutron star equation of state, tests of fundamental physics, and insight into the origin of the prompt emission. to increase the likelihood of these coincident detections, full sky... | burstcube: a cubesat for gravitational wave counterparts |
the space-based multi-band astronomical variable objects monitor (svom) is a french-chinese satellite mission dedicated to gamma-ray burst (grb) studies. the project was adopted in 2017 and started its detailed definition (phase c), before construction and launch foreseen in late 2021. with its set of 4 on-board instru... | the gamma-ray burst trigger eclairs on-board svom |
with the advent of the multi-messenger era of astronomy, that is the combined electromagnetic (em)/gravitational-wave (gw) observations and studies of neutron stars and black holes, the interest in short gamma-ray bursts (sgrbs) has increased tremendously. indeed, until the historic aug. 17, 2017 simultaneous detection... | physical characteristics of short grb from afterglow observational light curves |
the mas/corhel three-dimensional mhd model of the solar corona and solar wind has been applied to a wide variety of problems in solar and heliospheric physics. the output of the model can be used to simulate observed phenomena, such as euv, x-ray, and white-light images, as well as in situ plasma measurements, includin... | two-temperature, wave-turbulence-driven mhd simulations of the solar corona and the solar wind |
kirkpatrick-baez (k-b) optics offer a means of imaging soft x-rays with modest resolution and a multi-arc-minute field of view at a cost far below the conventional wolter design. such a low-cost system could be useful for dedicated, long time-line observation of astronomical x-ray sources from orbit. a k-b telescope co... | a modified kirkpatrick-baez design for a practical astronomical x-ray telescope |
recent astronomy studies observed the existence of hundreds of ice giants in the universe. ice is one of the major components of these ice giants. experimental studies on the physical properties of ice at high pressures are thus important for understanding the composition and evolution of these ice giants. here, we hav... | single-crystal elasticity of ice at high pressures |
fast neutrons (energies >0.5 mev) contribute to the total radiation exposure of space hardware and astronaut crew. they constitute a probe that enables a greater understanding of planetary atmospheric and surface compositions, and of particle acceleration in solar flares. however, neutrons are challenging to detect ... | the solar neutron tracking (sontrac) instrument |
we model the neupert effect that relates flare heating energy with the observed soft x-ray (sxr) emission. the common form of the neupert effect refers to the correlation between the time-integrated hard x-ray (hxr) or microwave light curve and the sxr light curve. in this study, instead, we use as the proxy for heatin... | the neupert effect of flare ultraviolet and soft x-ray emissions |
while reliably forecasting large solar flares days or even hours ahead of time remains an elusive goal of the space weather community, predicting the magnitude and duration of flare minutes after it starts may be attainable. in this effort, we examine over 20 years of goes xrs measurements, which include 170 x-class fl... | in-progress flare forecasting |
there is a clear need for new x-ray observations that can capture the full range of emission in flares (e.g., faint coronal sources near bright chromospheric sources), follow the intricate evolution of energy release and changes in morphology, and search for the signatures of impulsive energy release in even the quiesc... | anticipated particle-acceleration and plasma-heating results from the foxsi smex mission |
serendipitous x-ray surveys have been proven to be an efficient way to find rare objects - tidal disruption events, galaxy clusters, binary quasars, etc. as x-ray astronomy slowly enters the era of big data, an automated classification of x-ray sources becomes increasingly valuable. i present a revisited naive bayes cl... | mining the high-energy universe: a probabilistic, interpretable classification of x-ray sources for large x-ray surveys |
the energy range between 300 kev and 100 mev is an experimentally very difficult range and remained uncovered since the time of comptel. future instruments like e-astrogam can address all astrophysics issues left open by the current generation of instruments. in particular, a better angular resolution in the energy ran... | developments in space-based gamma-ray astronomy and the connection with cta |
the center for astrophysical plasma properties (capp) is a new center focusing on the spectroscopic properties of stars and accretion disks using “at-parameter” experiments. currently, these experiments use the x-ray output of the z machine at sandia national laboratories—the largest x-ray source in the world—to heat p... | from the telescope to the laboratory and back again: the center for astrophysical plasma properties |
the discovery of x-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the universe. in fact, the exploration of the x-ray sky during the 70s-90s has established x-ray astronomy as a fundamental field of astrophysics. today, the emission from astrophysical sources is by large bes... | simbol-x: a formation flight mission with an unprecedented imaging capability in the 0.5-80 kev energy band |
motivated by the work done to explore the winds from hot stars (lamers & cassinelli 1999), we develop a method for self consistently calculating force multipliers for type 1 and type 2 active galactic nuclei (agn), soft and hard start x-ray binaries (xrbs) spectral energy distributions (seds). we find that the ampl... | force multiplier calculations for x-ray binaries and active galactic nuclei |
solar coronal dimmings have been observed extensively in the past two decades. due to their close association with coronal mass ejections (cmes), there is a critical need to improve our understanding of the physical processes that cause dimmings and determine their relationship with cmes. in this study, we investigate ... | coronal mass ejections and dimmings: a comparative study using mhd simulations and sdo observations |
this chapter describes the use and development of reflective multilayer coatings for hard x-ray astronomy. these coatings are designed to have broad spectral response at x-ray energies above ∼10 kev, and are deposited onto mirror substrates used to construct grazing-incidence x-ray telescopes. the principles of operati... | x-ray multilayer coatings |
acis extract (ae), written in the idl language, provides innovative and automated solutions to the varied challenges found in the analysis of x-ray data taken by the acis instrument on nasa's chandra observatory. ae addresses complications found in many chandra projects: large numbers of point sources (hundreds to seve... | acis extract software package |
radiative transfer methods provide a path to uncover the intrinsic properties of astronomical objects from observations. the determination of the shape, size and brightness of many objects is complicated by the interaction of photons with the material in the intervening medium. in this thesis i have explored the use of... | seeing through the dark : probing structure and processes across galactic scales using monte carlo radiative transfer |
further to aavso alert notice 678, dr. margarita karovska (center for astrophysics|harvard & smithsonian) informs us that the symbiotic system v694 mon (mwc 560) is currently scheduled to be observed with the chandra x-ray satellite during the week (ut) of 27-jan-2020 to 03-feb-2020. when the exact time is known, t... | v694 mon (mwc 560) to be observed with chandra |
the era of time-domain astronomy has brought new challenges and opportunity to x-ray observational astronomy. recent discoveries indicate that fast x-ray transients, x-ray detected extrasolar planet transits and several other exotic events remain hidden in the rich data sets that x-ray telescopes such as chandra, xmm-n... | xander: x-ray anomaly detector |
in this work we deal with parametric inverse problems, which consist in recovering a finite number of parameters describing the structure of an unknown object, from indirect measurements. state-of-the-art methods for approximating a regularizing inverse operator by using a dataset of input-output pairs of the forward m... | approximation of discontinuous inverse operators with neural networks |
the 60cm bootes-5/jgt robotic telescope at observatorio astronomico nacional in san pedro martir (mexico) automatically followed up grb 210730a (sonbas et al., gcnc 30548) starting at 05:56:36 ut (~1 hr after trigger). within the swift/xrt error position (beardmore et al., gcnc 30550), no new optical afterglow is found... | grb 210730a: bootes-5/jgt and 2.2m caha telescopes optical limit |
"we observed grb 210702a (lien et al. gcn 30351) with the meerkat radio telescope array over two epochs beginning on 2021 july 11 12:16 utc (8.7 d after the burst) and 2021 july 23 18:16 utc (21.0 d after the burst), respectively. preliminary analysis reveals a brightening radio counterpart with 1.284 ghz flux density ... | grb 210702a: meerkat radio detection |
we report on new hubble space telescope (hst) observations of the near-infrared counterpart to gw170817 at a mid-time of 4.98 jan 2021 ut, 1236.45 days from merger (go-15886, pi fong). these observations consist of 3 orbits observed in wfc3/ir f140w for a total of 7.8 ks on-source exposure time. compared to previous f6... | gw170817: hst observations at 3.4 years from merger |
i will present xmmfitcat-z, an unique tool for the astronomical community to construct large and representative samples of x-ray sources by selecting them according to their spectral properties. xmmfitcat-z is an enhanced version of xmmfitcat, the xmm-newton spectral-fit database, which contains automated spectral-fitt... | xmmfitcat-z: the enhanced xmm-newton spectral-fit database by the inclusion of photometric redshifts |
classical loop-prominence systems associated with powerful solar flares have been observed since the 1930's. since their initial observations, loop prominence systems (lps) were a topic of particular interest for solar physicists as they seem to have a clear relationship with solar flares. the time evolution of loop pr... | the 2017 september 10 loop-prominence system: a polarization and density analysis |
in december, aas nova editor susanna kohler had the opportunity to fly aboard the nasa/dlr stratospheric observatory for infrared astronomy (sofia). this week were taking a look at that flight, as well as some of the recent science the observatory produced and published in an apj letters focus issue.one of sofias great... | focus on sofia: fifi-ls |
this study aims to uncover the signature of fuv explosive events (ees) in si iv full-disk mosaics (fdms) taken by the interface region imaging spectrograph (iris). the iris fdms allow for the opportunity to detect individual ees across the disk and accurately measure the disk-integrated spectrum both with and without t... | explosive event contribution to the iris si iv transition region lines of the sun-as-a-star |
longitudinal intensity oscillations generated in flare-heated coronal loops were recently observed with sdo/aia in 94 å and 131 å channels. these oscillations have been interpreted as standing or reflected propagating slow magnetoacoustic waves. they are mostly triggered by a circular-ribbon flare located at one footpo... | simulations of longitudinal oscillations in flaring coronal loops observed with sdo/aia |
halosat is a cubesat that is performing an all-sky survey of soft x-ray line emission from highly ionized oxygen with the goal of determining if hot halos gravitationally bound to galaxies make a significant contribution to the cosmological baryon budget. as of this writing, halosat has been conducting science operatio... | observing the galactic halo with halosat |
for almost 20 years a team of astronomers, theorists and experimentalists have investigated the creation of the famous pillars of the eagle nebula and similar parsec-scale structures at the boundaries of hii regions in molecular hydrogen clouds, using a combination of astronomical observations, astrophysical simulation... | nif discovery science eagle nebula |
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... | the next breakthroughs community program: chandra-vla observations of compact-object mergers |
observations of the sun in hard x-rays can provide insight into many solar phenomena which are not currently well-understood, including the mechanisms behind particle acceleration in flares. currently, rhessi is the only solar-dedicated spacecraft observing in the hard x-ray regime. though rhessi has greatly added to o... | analysis of microflares from the second sounding rocket flight of the focusing optics x-ray solar imager (foxsi-2) |
we consider a temporal response of relativistically broadened line spectrum of iron from black hole accretion irradiated by an x-ray echo under strong gravity. the physical condition of accreting gas is numerically calculated in the context of general relativistic hydrodynamics under steady-state axisymmetry in kerr ge... | iron line tomography of general relativistic hydrodynamic accretion around kerr black holes |
halosat was the first cubesat competitively funded by nasa's astrophysics division and performed a two-year, all-sky survey in the soft x-ray band. halosat's primary goal was to measure line emission from highly ionized oxygen within the halo of the milky way. however, it has also been used to study extended soft x-ray... | halosat — a cubesat that studied the hot galactic halo |
gamma-ray and multimessenger astrophysics are frontiers for discovery and uniquely provide access to the extreme processes that sculpt the universe. multimessenger astrophysics is one of the most exciting and rapidly advancing fields of science. as a priority theme of the astro2020 decadal survey report: new messengers... | amego-x mission overview |
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