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The dataset generation failed
Error code: DatasetGenerationError
Exception: UnicodeDecodeError
Message: 'utf-8' codec can't decode byte 0x9a in position 84056: invalid start byte
Traceback: Traceback (most recent call last):
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1995, in _prepare_split_single
for _, table in generator:
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/packaged_modules/csv/csv.py", line 195, in _generate_tables
for batch_idx, df in enumerate(csv_file_reader):
File "/src/services/worker/.venv/lib/python3.9/site-packages/pandas/io/parsers/readers.py", line 1843, in __next__
return self.get_chunk()
File "/src/services/worker/.venv/lib/python3.9/site-packages/pandas/io/parsers/readers.py", line 1985, in get_chunk
return self.read(nrows=size)
File "/src/services/worker/.venv/lib/python3.9/site-packages/pandas/io/parsers/readers.py", line 1923, in read
) = self._engine.read( # type: ignore[attr-defined]
File "/src/services/worker/.venv/lib/python3.9/site-packages/pandas/io/parsers/c_parser_wrapper.py", line 234, in read
chunks = self._reader.read_low_memory(nrows)
File "parsers.pyx", line 850, in pandas._libs.parsers.TextReader.read_low_memory
File "parsers.pyx", line 905, in pandas._libs.parsers.TextReader._read_rows
File "parsers.pyx", line 874, in pandas._libs.parsers.TextReader._tokenize_rows
File "parsers.pyx", line 891, in pandas._libs.parsers.TextReader._check_tokenize_status
File "parsers.pyx", line 2053, in pandas._libs.parsers.raise_parser_error
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x9a in position 84056: invalid start byte
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1529, in compute_config_parquet_and_info_response
parquet_operations = convert_to_parquet(builder)
File "/src/services/worker/src/worker/job_runners/config/parquet_and_info.py", line 1154, in convert_to_parquet
builder.download_and_prepare(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1027, in download_and_prepare
self._download_and_prepare(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1122, in _download_and_prepare
self._prepare_split(split_generator, **prepare_split_kwargs)
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 1882, in _prepare_split
for job_id, done, content in self._prepare_split_single(
File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/builder.py", line 2038, in _prepare_split_single
raise DatasetGenerationError("An error occurred while generating the dataset") from e
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title string | heading string | content string | tokens int64 |
|---|---|---|---|
Radiation | Summary | In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:
electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ)
particle radiation, such as alph... | 600 |
Radiation | Ionizing radiation | Radiation with sufficiently high energy can ionize atoms; that is to say it can knock electrons off atoms, creating ions. Ionization occurs when an electron is stripped (or "knocked out") from an electron shell of the atom, which leaves the atom with a net positive charge. Because living cells and, more importantly, th... | 730 |
Radiation | Ultraviolet radiation | Ultraviolet, of wavelengths from 10 nm to 125 nm, ionizes air molecules, causing it to be strongly absorbed by air and by ozone (O3) in particular. Ionizing UV therefore does not penetrate Earth's atmosphere to a significant degree, and is sometimes referred to as vacuum ultraviolet. Although present in space, this par... | 299 |
Radiation | X-rays | X-rays are electromagnetic waves with a wavelength less than about 10−9 m (greater than 3x1017 Hz and 1,240 eV). A smaller wavelength corresponds to a higher energy according to the equation E=h c/λ. ("E" is Energy; "h" is Planck's constant; "c" is the speed of light; "λ" is wavelength.) When an X-ray photon collides w... | 274 |
Radiation | Gamma radiation | Gamma (γ) radiation consists of photons with a wavelength less than 3x10−11 meters (greater than 1019 Hz and 41.4 keV). Gamma radiation emission is a nuclear process that occurs to rid an unstable nucleus of excess energy after most nuclear reactions. Both alpha and beta particles have an electric charge and mass, and ... | 275 |
Radiation | Alpha radiation | Alpha particles are helium-4 nuclei (two protons and two neutrons). They interact with matter strongly due to their charges and combined mass, and at their usual velocities only penetrate a few centimeters of air, or a few millimeters of low density material (such as the thin mica material which is specially placed in ... | 289 |
Radiation | Beta radiation | Beta-minus (β−) radiation consists of an energetic electron. It is more penetrating than alpha radiation but less than gamma. Beta radiation from radioactive decay can be stopped with a few centimeters of plastic or a few millimeters of metal. It occurs when a neutron decays into a proton in a nucleus, releasing the be... | 206 |
Radiation | Neutron radiation | Neutrons are categorized according to their speed/energy. Neutron radiation consists of free neutrons. These neutrons may be emitted during either spontaneous or induced nuclear fission. Neutrons are rare radiation particles; they are produced in large numbers only where chain reaction fission or fusion reactions are a... | 635 |
Radiation | Cosmic radiation | There are two sources of high energy particles entering the Earth's atmosphere from outer space: the sun and deep space. The sun continuously emits particles, primarily free protons, in the solar wind, and occasionally augments the flow hugely with coronal mass ejections (CME).
The particles from deep space (inter- and... | 211 |
Radiation | Non-ionizing radiation | The kinetic energy of particles of non-ionizing radiation is too small to produce charged ions when passing through matter. For non-ionizing electromagnetic radiation (see types below), the associated particles (photons) have only sufficient energy to change the rotational, vibrational or electronic valence configurati... | 437 |
Radiation | Ultraviolet light | As noted above, the lower part of the spectrum of ultraviolet, called soft UV, from 3 eV to about 10 eV, is non-ionizing. However, the effects of non-ionizing ultraviolet on chemistry and the damage to biological systems exposed to it (including oxidation, mutation, and cancer) are such that even this part of ultraviol... | 82 |
Radiation | Visible light | Light, or visible light, is a very narrow range of electromagnetic radiation of a wavelength that is visible to the human eye, or 380–750 nm which equates to a frequency range of 790 to 400 THz respectively. More broadly, physicists use the term "light" to mean electromagnetic radiation of all wavelengths, whether visi... | 72 |
Radiation | Infrared | Infrared (IR) light is electromagnetic radiation with a wavelength between 0.7 and 300 micrometers, which corresponds to a frequency range between 430 and 1 THz respectively. IR wavelengths are longer than that of visible light, but shorter than that of microwaves. Infrared may be detected at a distance from the radiat... | 142 |
Radiation | Microwave | Microwaves are electromagnetic waves with wavelengths ranging from as short as one millimeter to as long as one meter, which equates to a frequency range of 300 MHz to 300 GHz. This broad definition includes both UHF and EHF (millimeter waves), but various sources use different other limits. In all cases, microwaves in... | 116 |
Radiation | Radio waves | Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Like all other electromagnetic waves, they travel at the speed of light. Naturally occurring radio waves are made by lightning, or by certain astronomical objects. Artificially generated radi... | 184 |
Radiation | Very low frequency | Very low frequency (VLF) refers to a frequency range of 30 Hz to 3 kHz which corresponds to wavelengths of 100,000 to 10,000 meters respectively. Since there is not much bandwidth in this range of the radio spectrum, only the very simplest signals can be transmitted, such as for radio navigation. Also known as the myri... | 103 |
Radiation | Extremely low frequency | Extremely low frequency (ELF) is radiation frequencies from 3 to 30 Hz (108 to 107 meters respectively). In atmosphere science, an alternative definition is usually given, from 3 Hz to 3 kHz. In the related magnetosphere science, the lower frequency electromagnetic oscillations (pulsations occurring below ~3 Hz) are co... | 115 |
Radiation | Thermal radiation (heat) | Thermal radiation is a common synonym for infrared radiation emitted by objects at temperatures often encountered on Earth. Thermal radiation refers not only to the radiation itself, but also the process by which the surface of an object radiates its thermal energy in the form of black body radiation. Infrared or red r... | 195 |
Radiation | Black-body radiation | Black-body radiation is an idealized spectrum of radiation emitted by a body that is at a uniform temperature. The shape of the spectrum and the total amount of energy emitted by the body is a function of the absolute temperature of that body. The radiation emitted covers the entire electromagnetic spectrum and the int... | 383 |
Radiation | Discovery | Electromagnetic radiation of wavelengths other than visible light were discovered in the early 19th century. The discovery of infrared radiation is ascribed to William Herschel, the astronomer. Herschel published his results in 1800 before the Royal Society of London. Herschel, like Ritter, used a prism to refract ligh... | 690 |
Radiation | Medicine | Radiation and radioactive substances are used for diagnosis, treatment, and research. X-rays, for example, pass through muscles and other soft tissue but are stopped by dense materials. This property of X-rays enables doctors to find broken bones and to locate cancers that might be growing in the body. Doctors also fin... | 171 |
Radiation | Communication | All modern communication systems use forms of electromagnetic radiation. Variations in the intensity of the radiation represent changes in the sound, pictures, or other information being transmitted. For example, a human voice can be sent as a radio wave or microwave by making the wave vary to corresponding variations ... | 84 |
Radiation | Science | Researchers use radioactive atoms to determine the age of materials that were once part of a living organism. The age of such materials can be estimated by measuring the amount of radioactive carbon they contain in a process called radiocarbon dating. Similarly, using other radioactive elements, the age of rocks and ot... | 171 |
Radiation | Possible damage to health and environment from certain types of radiation | Radiation is not always dangerous, and not all types of radiation are equally dangerous, contrary to several common medical myths. For example, although bananas contain naturally occurring radioactive isotopes, particularly potassium-40 (40K), which emit ionizing radiation when undergoing radioactive decay, the levels ... | 381 |
Gravitational wave | Summary | Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as waves similar to electromagn... | 489 |
Gravitational wave | Introduction | In Einstein's general theory of relativity, gravity is treated as a phenomenon resulting from the curvature of spacetime. This curvature is caused by the presence of mass. Generally, the more mass that is contained within a given volume of space, the greater the curvature of spacetime will be at the boundary of its vol... | 592 |
Gravitational wave | Speed of gravity | The speed of gravitational waves in the general theory of relativity is equal to the speed of light in a vacuum, c. Within the theory of special relativity, the constant c is not only about light; instead it is the highest possible speed for any interaction in nature. Formally, c is a conversion factor for changing the... | 251 |
Gravitational wave | History | The possibility of gravitational waves was discussed in 1893 by Oliver Heaviside, using the analogy between the inverse-square law of gravitation and the electrostatic force.. In 1905, Henri Poincaré proposed gravitational waves, emanating from a body and propagating at the speed of light, as being required by the Lore... | 534 |
Gravitational wave | Effects of passing | Gravitational waves are constantly passing Earth; however, even the strongest have a minuscule effect and their sources are generally at a great distance. For example, the waves given off by the cataclysmic final merger of GW150914 reached Earth after travelling over a billion light-years, as a ripple in spacetime that... | 825 |
Gravitational wave | Energy, momentum, and angular momentum | Water waves, sound waves, and electromagnetic waves are able to carry energy, momentum, and angular momentum and by doing so they carry those away from the source. Gravitational waves perform the same function. Thus, for example, a binary system loses angular momentum as the two orbiting objects spiral towards each oth... | 267 |
Gravitational wave | Redshifting | Like electromagnetic waves, gravitational waves should exhibit shifting of wavelength and frequency due to the relative velocities of the source and observer (the Doppler effect), but also due to distortions of spacetime, such as cosmic expansion. This is the case even though gravity itself is a cause of distortions of... | 88 |
Gravitational wave | Quantum gravity, wave-particle aspects, and graviton | In the framework of quantum field theory, the graviton is the name given to a hypothetical elementary particle speculated to be the force carrier that mediates gravity. However the graviton is not yet proven to exist, and no scientific model yet exists that successfully reconciles general relativity, which describes gr... | 235 |
Gravitational wave | Significance for study of the early universe | Due to the weakness of the coupling of gravity to matter, gravitational waves experience very little absorption or scattering, even as they travel over astronomical distances. In particular, gravitational waves are expected to be unaffected by the opacity of the very early universe. In these early phases, space had not... | 118 |
Gravitational wave | Determining direction of travel | The difficulty in directly detecting gravitational waves means it is also difficult for a single detector to identify by itself the direction of a source. Therefore, multiple detectors are used, both to distinguish signals from other "noise" by confirming the signal is not of earthly origin, and also to determine direc... | 196 |
Gravitational wave | Gravitational wave astronomy | During the past century, astronomy has been revolutionized by the use of new methods for observing the universe. Astronomical observations were initially made using visible light. Galileo Galilei pioneered the use of telescopes to enhance these observations. However, visible light is only a small portion of the electro... | 469 |
Gravitational wave | Indirect detection | Although the waves from the Earth–Sun system are minuscule, astronomers can point to other sources for which the radiation should be substantial. One important example is the Hulse–Taylor binary – a pair of stars, one of which is a pulsar. The characteristics of their orbit can be deduced from the Doppler shifting of ... | 662 |
Gravitational wave | Difficulties | Gravitational waves are not easily detectable. When they reach the Earth, they have a small amplitude with strain approximately 10−21, meaning that an extremely sensitive detector is needed, and that other sources of noise can overwhelm the signal. Gravitational waves are expected to have frequencies 10−16 Hz < f < 104... | 68 |
Gravitational wave | Negative-mass plasma | One possible explanation for the difficulties with direct observation of gravitational waves was proposed by cosmologists Saoussen Mbarek and Manu Paranjape after they demonstrated the possible existence of negative mass without violating Einsteinian relativity. Earlier research dismissed the concept due to seemingly v... | 165 |
Gravitational wave | Ground-based detectors | Though the Hulse–Taylor observations were very important, they give only indirect evidence for gravitational waves. A more conclusive observation would be a direct measurement of the effect of a passing gravitational wave, which could also provide more information about the system that generated it. Any such direct det... | 161 |
Gravitational wave | Resonant antennas | A simple device theorised to detect the expected wave motion is called a Weber bar – a large, solid bar of metal isolated from outside vibrations. This type of instrument was the first type of gravitational wave detector. Strains in space due to an incident gravitational wave excite the bar's resonant frequency and co... | 529 |
Gravitational wave | Interferometers | A more sensitive class of detector uses a laser Michelson interferometer to measure gravitational-wave induced motion between separated 'free' masses. This allows the masses to be separated by large distances (increasing the signal size); a further advantage is that it is sensitive to a wide range of frequencies (not j... | 614 |
Gravitational wave | Einstein@Home | The simplest gravitational waves are those with constant frequency. The waves given off by a spinning, non-axisymmetric neutron star would be approximately monochromatic: a pure tone in acoustics. Unlike signals from supernovae or binary black holes, these signals evolve little in amplitude or frequency over the period... | 202 |
Gravitational wave | Space-based interferometers | Space-based interferometers, such as LISA and DECIGO, are also being developed. LISA's design calls for three test masses forming an equilateral triangle, with lasers from each spacecraft to each other spacecraft forming two independent interferometers. LISA is planned to occupy a solar orbit trailing the Earth, with e... | 118 |
Gravitational wave | Using pulsar timing arrays | Pulsars are rapidly rotating stars. A pulsar emits beams of radio waves that, like lighthouse beams, sweep through the sky as the pulsar rotates. The signal from a pulsar can be detected by radio telescopes as a series of regularly spaced pulses, essentially like the ticks of a clock. GWs affect the time it takes the p... | 423 |
Gravitational wave | Primordial gravitational wave | Primordial gravitational waves are gravitational waves observed in the cosmic microwave background. They were allegedly detected by the BICEP2 instrument, an announcement made on 17 March 2014, which was withdrawn on 30 January 2015 ("the signal can be entirely attributed to dust in the Milky Way"). | 61 |
Gravitational wave | LIGO and Virgo observations | On 11 February 2016, the LIGO collaboration announced the first observation of gravitational waves, from a signal detected at 09:50:45 GMT on 14 September 2015 of two black holes with masses of 29 and 36 solar masses merging about 1.3 billion light-years away. During the final fraction of a second of the merger, it rel... | 653 |
Gravitational wave | Microscopic sources | In 1964 Halpern and Laurent theoretically proved that gravitational spin-2 electron transitions are possible in atoms. Compared to electric and magnetic transitions the emission probability is extremely low. Stimulated emission was discussed for increasing the efficiency of the process. Due to the lack of mirrors or re... | 301 |
Gravitational wave | In fiction | An episode of the 1962 Russian science-fiction novel Space Apprentice by Arkady and Boris Strugatsky shows the experiment monitoring the propagation of gravitational waves at the expense of annihilating a chunk of asteroid 15 Eunomia the size of Mount Everest.In Stanislaw Lem's 1986 novel Fiasco, a "gravity gun" or "gr... | 206 |
Gamma-ray burst | Summary | In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milliseconds to several hours. After an initial flash of gamma rays, a longer-lived... | 415 |
Gamma-ray burst | History | Gamma-ray bursts were first observed in the late 1960s by the U.S. Vela satellites, which were built to detect gamma radiation pulses emitted by nuclear weapons tested in space. The United States suspected that the Soviet Union might attempt to conduct secret nuclear tests after signing the Nuclear Test Ban Treaty in 1... | 391 |
Gamma-ray burst | Counterpart objects as candidate sources | For decades after the discovery of GRBs, astronomers searched for a counterpart at other wavelengths: i.e., any astronomical object in positional coincidence with a recently observed burst. Astronomers considered many distinct classes of objects, including white dwarfs, pulsars, supernovae, globular clusters, quasars, ... | 187 |
Gamma-ray burst | Afterglow | Several models for the origin of gamma-ray bursts postulated that the initial burst of gamma rays should be followed by afterglow: slowly fading emission at longer wavelengths created by collisions between the burst ejecta and interstellar gas. Early searches for this afterglow were unsuccessful, largely because it is ... | 410 |
Gamma-ray burst | More recent instruments | BeppoSAX functioned until 2002 and CGRO (with BATSE) was deorbited in 2000. However, the revolution in the study of gamma-ray bursts motivated the development of a number of additional instruments designed specifically to explore the nature of GRBs, especially in the earliest moments following the explosion. The first ... | 619 |
Gamma-ray burst | Classification | The light curves of gamma-ray bursts are extremely diverse and complex. No two gamma-ray burst light curves are identical, with large variation observed in almost every property: the duration of observable emission can vary from milliseconds to tens of minutes, there can be a single peak or several individual subpulses... | 315 |
Gamma-ray burst | Short gamma-ray bursts | Events with a duration of less than about two seconds are classified as short gamma-ray bursts. These account for about 30% of gamma-ray bursts, but until 2005, no afterglow had been successfully detected from any short event and little was known about their origins. Since then, several dozen short gamma-ray burst afte... | 416 |
Gamma-ray burst | Long gamma-ray bursts | Most observed events (70%) have a duration of greater than two seconds and are classified as long gamma-ray bursts. Because these events constitute the majority of the population and because they tend to have the brightest afterglows, they have been observed in much greater detail than their short counterparts. Almost ... | 166 |
Gamma-ray burst | Ultra-long gamma-ray bursts | These events are at the tail end of the long GRB duration distribution, lasting more than 10,000 seconds. They have been proposed to form a separate class, caused by the collapse of a blue supergiant star, a tidal disruption event or a new-born magnetar. Only a small number have been identified to date, their primary c... | 185 |
Gamma-ray burst | Energetics and beaming | Gamma-ray bursts are very bright as observed from Earth despite their typically immense distances. An average long GRB has a bolometric flux comparable to a bright star of our galaxy despite a distance of billions of light years (compared to a few tens of light years for most visible stars). Most of this energy is rele... | 609 |
Gamma-ray burst | Progenitors | Because of the immense distances of most gamma-ray burst sources from Earth, identification of the progenitors, the systems that produce these explosions, is challenging. The association of some long GRBs with supernovae and the fact that their host galaxies are rapidly star-forming offer very strong evidence that long... | 567 |
Gamma-ray burst | Tidal disruption events | This new class of GRB-like events was first discovered through the detection of GRB 110328A by the Swift Gamma-Ray Burst Mission on 28 March 2011. This event had a gamma-ray duration of about 2 days, much longer than even ultra-long GRBs, and was detected in X-rays for many months. It occurred at the center of a small ... | 251 |
Gamma-ray burst | Emission mechanisms | The means by which gamma-ray bursts convert energy into radiation remains poorly understood, and as of 2010 there was still no generally accepted model for how this process occurs. Any successful model of GRB emission must explain the physical process for generating gamma-ray emission that matches the observed diversit... | 395 |
Gamma-ray burst | Rate of occurrence and potential effects on life | Gamma ray bursts can have harmful or destructive effects on life. Considering the universe as a whole, the safest environments for life similar to that on Earth are the lowest density regions in the outskirts of large galaxies. Our knowledge of galaxy types and their distribution suggests that life as we know it can on... | 444 |
Gamma-ray burst | Effects on Earth | Earth's atmosphere is very effective at absorbing high energy electromagnetic radiation such as x-rays and gamma rays, so these types of radiation would not reach any dangerous levels at the surface during the burst event itself. The immediate effect on life on Earth from a GRB within a few kiloparsecs would only be a ... | 482 |
Gamma-ray burst | Hypothetical effects on Earth in the past | There is a very good chance (but no certainty) that at least one lethal GRB took place during the past 5 billion years close enough to Earth as to significantly damage life. There is a 50% chance that such a lethal GRB took place within two kiloparsecs of Earth during the last 500 million years, causing one of the majo... | 319 |
Gamma-ray burst | GRB candidates in the Milky Way | No gamma-ray bursts from within our own galaxy, the Milky Way, have been observed, and the question of whether one has ever occurred remains unresolved. In light of evolving understanding of gamma-ray bursts and their progenitors, the scientific literature records a growing number of local, past, and future GRB candida... | 187 |
Chandra X-ray Observatory | Summary | The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the Space Shuttle Columbia during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enab... | 246 |
Chandra X-ray Observatory | History | In 1976 the Chandra X-ray Observatory (called AXAF at the time) was proposed to NASA by Riccardo Giacconi and Harvey Tananbaum. Preliminary work began the following year at Marshall Space Flight Center (MSFC) and the Smithsonian Astrophysical Observatory (SAO), where the telescope is now operated for NASA at the Chandr... | 832 |
Chandra X-ray Observatory | Example discoveries | The data gathered by Chandra has greatly advanced the field of X-ray astronomy. Here are some examples of discoveries supported by observations from Chandra:
The first light image, of supernova remnant Cassiopeia A, gave astronomers their first glimpse of the compact object at the center of the remnant, probably a neu... | 915 |
Chandra X-ray Observatory | Technical description | Unlike optical telescopes which possess simple aluminized parabolic surfaces (mirrors), X-ray telescopes generally use a Wolter telescope consisting of nested cylindrical paraboloid and hyperboloid surfaces coated with iridium or gold. X-ray photons would be absorbed by normal mirror surfaces, so mirrors with a low gra... | 385 |
Chandra X-ray Observatory | Instruments | The Science Instrument Module (SIM) holds the two focal plane instruments, the Advanced CCD Imaging Spectrometer (ACIS) and the High Resolution Camera (HRC), moving whichever is called for into position during an observation.
ACIS consists of 10 CCD chips and provides images as well as spectral information of the objec... | 285 |
Lynx X-ray Observatory | Summary | The Lynx X-ray Observatory (Lynx) is a NASA-funded Large Mission Concept Study commissioned as part of the National Academy of Sciences 2020 Astronomy and Astrophysics Decadal Survey. The concept study phase is complete as of August 2019, and the Lynx final report has been submitted to the Decadal Survey for prioritiza... | 121 |
Lynx X-ray Observatory | Background | In 2016, following recommendations laid out in the so-called Astrophysics Roadmap of 2013, NASA established four space telescope concept studies for future Large strategic science missions. In addition to Lynx (originally called X-ray Surveyor in the Roadmap document), they are the Habitable Exoplanet Imaging Mission (... | 303 |
Lynx X-ray Observatory | Scientific objectives | According to the concept study's Final Report, the Lynx Design Reference Mission was intentionally optimized to enable major advances in the following three astrophysical discovery areas:
The dawn of black holes (Chapter 1 of the Lynx Report)
The drivers of galaxy formation and evolution (Lynx Report, Chapter 2)
The e... | 239 |
Lynx X-ray Observatory | Spacecraft | As described in Chapters 6-10 of the concept study's Final Report, Lynx is designed as an X-ray observatory with a grazing incidence X-ray telescope and detectors that record the position, energy, and arrival time of individual X-ray photons. Post-facto aspect reconstruction leads to modest requirements on pointing pre... | 203 |
Lynx X-ray Observatory | Payload | The major advances in sensitivity, spatial, and spectral resolution in the Lynx Design Reference Mission are enabled by the spacecraft's payload, namely the mirror assembly and suite of three science instruments.. The Lynx Report notes that each of the payload elements features state-of-the-art technologies while also ... | 567 |
Lynx X-ray Observatory | Mission Operations | The Chandra X-ray Observatory experience provides the blueprint for developing the systems required to operate Lynx, leading to a significant cost reduction relative to starting from scratch. This starts with a single prime contractor for the science and operations center, staffed by a seamless, integrated team of scie... | 264 |
Lynx X-ray Observatory | Estimated cost | The cost of the Lynx X-ray Observatory is estimated to be between US$4.8 billion to US$6.2 billion (in FY20 dollars at 40% and 70% confidence levels, respectively). This estimated cost range includes the launch vehicle, cost reserves, and funding for five years of mission operations, while excluding potential foreign c... | 125 |
X-Ray Imaging and Spectroscopy Mission | Summary | The X-Ray Imaging and Spectroscopy Mission (XRISM, pronounced "crism"), formerly the X-ray Astronomy Recovery Mission (XARM), is an X-ray astronomy satellite of the Japan Aerospace Exploration Agency (JAXA) to provide breakthroughs in the study of structure formation of the universe, outflows from galaxy nuclei, and da... | 266 |
X-Ray Imaging and Spectroscopy Mission | Overview | With the retirement of Suzaku in September 2015, and the detectors onboard Chandra X-ray Observatory and XMM-Newton operating for more than 15 years and gradually aging, the failure of Hitomi meant that X-ray astronomers will have a 13-year blank period in soft X-ray observation, until the launch of ATHENA in 2035. Thi... | 405 |
X-Ray Imaging and Spectroscopy Mission | Changes from Hitomi | The X-ray Imaging and Spectroscopy Mission will be one of the first projects for ISAS to place a separate project manager (PM) and a primary investigator (PI). This measure was taken as part of ISAS's reform in project management to prevent the recurrence of the Hitomi accident. In traditional ISAS missions, the PM was... | 448 |
X-Ray Imaging and Spectroscopy Mission | History | Following the premature termination of the Hitomi mission, on 14 June 2016 JAXA announced their proposal to rebuild the satellite. The XARM pre-project preparation team was formed in October 2016. In the U.S. side, formulation began in the summer of 2017. In June 2017, ESA announced that they will participate in XRISM ... | 78 |
X-Ray Imaging and Spectroscopy Mission | Instruments | XRISM will carry two instruments for studying the soft X-ray energy range, Resolve and Xtend. The satellite will have telescopes for each of the instruments, SXT-I (Soft X-ray Telescope for Imager) and SXT-S (Soft X-ray Telescope for Spectrometer). The pair of telescopes will have a focal length of 5.6 m (18 ft). | 86 |
X-Ray Imaging and Spectroscopy Mission | Resolve | Resolve is an X-ray micro calorimeter developed by NASA and the Goddard Space Flight Center. The instrument will likely not be a complete remanufacture of Hitomi's SXS, as there are some space-qualified hardware left from developing SXS, and these spare parts may be utilized to build Resolve. | 68 |
X-Ray Imaging and Spectroscopy Mission | Xtend | Xtend is an X-ray CCD camera. Unlike Resolve, which will be a "built-to-print" version of its predecessor, Xtend differs in that its energy resolution will be improved from Hitomi's SXI. | 54 |
Far-infrared Outgoing Radiation Understanding and Monitoring | Summary | FORUM (Far-infrared Outgoing Radiation Understanding and Monitoring) is an Earth observing satellite that is scheduled to launch in 2027.The FORUM mission is led by the European Space Agency (ESA) and has as its main goal the study of the Earth's radiation budget. It is expected that FORUM's measurements will be improv... | 88 |
Far-infrared Outgoing Radiation Understanding and Monitoring | Background | On 24 September 2019, ESA announced that FORUM was selected to become the ninth Earth Explorer mission, beating the Sea surface KInematics Multiscale monitoring (SKIM) proposal following a two-year feasibility study phase.The main scientific purpose of FORUM is to better understand the Earth's radiation budget - the ba... | 275 |
IXPE | Summary | Imaging X-ray Polarimetry Explorer, commonly known as IXPE or SMEX-14, is a space observatory with three identical telescopes designed to measure the polarization of cosmic X-rays of black holes, neutron stars, and pulsars. The observatory, which was launched on 9 December 2021, is an international collaboration betwee... | 206 |
IXPE | Overview | The IXPE mission was announced on 3 January 2017 and was launched on 9 December 2021. The international collaboration was signed in June 2017, when the Italian Space Agency (ASI) committed to provide the X-ray polarization detectors. The estimated cost of the mission and its two-year operation is US$188 million (the la... | 321 |
IXPE | Objectives | The technical and science objectives include:
Improve polarization sensitivity by two orders of magnitude over the X-ray polarimeter aboard the Orbiting Solar Observatory 8
Provide simultaneous spectral, spatial, and temporal measurements
Determine the geometry and the emission mechanism of active galactic nuclei and m... | 117 |
IXPE | Telescopes | The space observatory features three identical telescopes designed to measure the polarization of cosmic X-rays. The polarization-sensitive detector was invented and developed by Italian scientists of the Istituto Nazionale di AstroFisica (INAF) and the Istituto Nazionale di Fisica Nucleare (INFN) and was refined over ... | 79 |
IXPE | Principle | IXPE's payload is a set of three identical imaging X-ray polarimetry systems mounted on a common optical bench and co-aligned with the pointing axis of the spacecraft. Each system operates independently for redundancy and comprises a mirror module assembly that focuses X-rays onto a polarization-sensitive imaging detec... | 205 |
IXPE | Launch profile | IXPE was launched on 9 December 2021 on a SpaceX Falcon 9 (B1061.5) from LC-39A at NASA's Kennedy Space Center in Florida. The relatively small size and mass of the observatory falls well short of the normal capacity of SpaceX's Falcon 9 launch vehicle. However, Falcon 9 had to work to get IXPE into the correct orbit b... | 342 |
IXPE | Operations | IXPE is built to last for two years. After that it may be retired and deorbited or given an extended mission.
After launch and deployment of the IXPE spacecraft, NASA pointed the spacecraft at 1ES 1959+650, a black hole, and SMC X-1, a pulsar, for calibration. After that the spacecraft observed its first science target... | 168 |
IXPE | Results | In May 2022 the first study of IXPE hinted the possibility of vacuum birefringence on 4U 0142+61 and in August another study looked at centaurus A measuring low polarization degree, suggesting that the X-ray emission is coming from a scattering process rather than arising directly from the accelerated particles of the ... | 69 |
Astrophysical X-ray source | Summary | Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays.
Several types of astrophysical objects emit X-rays. They include galaxy clusters, black holes in active galactic nuclei (AGN), galactic objects such as supernova remnants, stars, and binary stars contai... | 279 |
Astrophysical X-ray source | Galaxy clusters | Clusters of galaxies are formed by the merger of smaller units of matter, such as galaxy groups or individual galaxies. The infalling material (which contains galaxies, gas and dark matter) gains kinetic energy as it falls into the cluster's gravitational potential well. The infalling gas collides with gas already in t... | 192 |
Astrophysical X-ray source | Quasars | A quasi-stellar radio source (quasar) is a very energetic and distant galaxy with an active galactic nucleus (AGN). QSO 0836+7107 is a Quasi-Stellar Object (QSO) that emits baffling amounts of radio energy. This radio emission is caused by electrons spiraling (thus accelerating) along magnetic fields producing cyclotro... | 277 |
Astrophysical X-ray source | Seyfert galaxies | Seyfert galaxies are a class of galaxies with nuclei that produce spectral line emission from highly ionized gas. They are a subclass of active galactic nuclei (AGN), and are thought to contain supermassive black holes. | 50 |
Astrophysical X-ray source | X-ray bright galaxies | The following early-type galaxies (NGCs) have been observed to be X-ray bright due to hot gaseous coronae: NGC 315, 1316, 1332, 1395, 2563, 4374, 4382, 4406, 4472, 4594, 4636, 4649, and 5128. The X-ray emission can be explained as thermal bremsstrahlung from hot gas (0.5–1.5 keV). | 103 |
Astrophysical X-ray source | Ultraluminous X-ray sources | Ultraluminous X-ray sources (ULXs) are pointlike, nonnuclear X-ray sources with luminosities above the Eddington limit of 3 × 1032 W for a 20 M☉ black hole. Many ULXs show strong variability and may be black hole binaries. To fall into the class of intermediate-mass black holes (IMBHs), their luminosities, thermal disk... | 238 |
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