Multiwavelength observations of XTE J1118+480`s outburst
... 30% of sources detected by INTEGRAL/IBIS were not known. 80% of Norma sources are X-ray pulsars, high spin periods Spectra typical of neutron stars No radio emission 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local ...
... 30% of sources detected by INTEGRAL/IBIS were not known. 80% of Norma sources are X-ray pulsars, high spin periods Spectra typical of neutron stars No radio emission 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local ...
2015 SAO Summer Intern AAS Abstracts - Harvard
... throughout our Galaxy as well as others, with the star formation rate (SFR) in a given region being proportional to the amount of gas above a threshold density. The Central Molecular Zone (CMZ) of our Galaxy is an excellent place to test these models. It is home to the highest amount of dense, molec ...
... throughout our Galaxy as well as others, with the star formation rate (SFR) in a given region being proportional to the amount of gas above a threshold density. The Central Molecular Zone (CMZ) of our Galaxy is an excellent place to test these models. It is home to the highest amount of dense, molec ...
are coronae of late-type stars made of solar-like structures? the x
... particular, this work shows that stellar coronae can be composed of X-ray–emitting structures similar to those present in the solar corona. To this end we use a large set of ROSAT PSPC observations of late-type stars of all spectral types and activity levels and a large set of solar X-ray data colle ...
... particular, this work shows that stellar coronae can be composed of X-ray–emitting structures similar to those present in the solar corona. To this end we use a large set of ROSAT PSPC observations of late-type stars of all spectral types and activity levels and a large set of solar X-ray data colle ...
Chapter 14 Neutron Stars and Black holes
... 17. What observational evidence do we have that stellar death black holes really exist? a. Hollowed-out green spheres are sucking up matter in star forming regions and emitting gamma rays. b. Some X-ray binaries have an unseen object with masses greater than 3 solar masses. c. Some X-ray binaries em ...
... 17. What observational evidence do we have that stellar death black holes really exist? a. Hollowed-out green spheres are sucking up matter in star forming regions and emitting gamma rays. b. Some X-ray binaries have an unseen object with masses greater than 3 solar masses. c. Some X-ray binaries em ...
ppt - WISH
... z > 1.5 represents a key period where such structures are collapsing and attaining virial equilibrium optical-IR searches + photo-z will detect clusters - but a lot of filaments, LSS and projections as well X-ray plus SZ turns this into an opportunity: we can identify virial and non-virial structure ...
... z > 1.5 represents a key period where such structures are collapsing and attaining virial equilibrium optical-IR searches + photo-z will detect clusters - but a lot of filaments, LSS and projections as well X-ray plus SZ turns this into an opportunity: we can identify virial and non-virial structure ...
Chapter 14
... the kinds of objects that remain after a massive star dies. How strange and wonderful that we humans can talk about places in the universe where gravity is so strong it bends space, slows time, and curves light back on itself! To carry on these discussions, astronomers have learned to use the langua ...
... the kinds of objects that remain after a massive star dies. How strange and wonderful that we humans can talk about places in the universe where gravity is so strong it bends space, slows time, and curves light back on itself! To carry on these discussions, astronomers have learned to use the langua ...
Coronal Mass Ejections and Angular Momentum Loss in Young Stars
... a significant role in stellar rotation evolution after the star has ceased accreting. Our Figs. 1 and 2 illustrate a critical selection effect in performing this kind of calculation: we only have data for the most active young stars, or the star conveniently located at 1 AU. There is a dearth of dat ...
... a significant role in stellar rotation evolution after the star has ceased accreting. Our Figs. 1 and 2 illustrate a critical selection effect in performing this kind of calculation: we only have data for the most active young stars, or the star conveniently located at 1 AU. There is a dearth of dat ...
Ultraluminous X-ray Sources in Andromeda Galaxy
... earlier, the very first X-ray observations of ULXs were conducted with Einstein, followed by ROSAT-HRI. There have been a lot more detections of ULXs after the introduction of the new era of X-ray astronomy with XMM-Newton, Swift and Chandra telescopes. In general, the data obtained with these teles ...
... earlier, the very first X-ray observations of ULXs were conducted with Einstein, followed by ROSAT-HRI. There have been a lot more detections of ULXs after the introduction of the new era of X-ray astronomy with XMM-Newton, Swift and Chandra telescopes. In general, the data obtained with these teles ...
CANGAROO and VHE γ-ray Astronomy: Past, present and future
... Estimation of the flux is affected by several factors: • ΔӨ : depending on if radiation is regarded as from “point source” or “extended” • Spectral shape as a function of location • (Effects due to sky noise of background photons?) ...
... Estimation of the flux is affected by several factors: • ΔӨ : depending on if radiation is regarded as from “point source” or “extended” • Spectral shape as a function of location • (Effects due to sky noise of background photons?) ...
X-Ray and Extreme Ultraviolet Emission from Comets
... Astrophysical X-ray emission is generally found to originate from hot collisional plasmas, such as the million-degree gas found in the solar corona (e.g., Foukal, 1990), the 100million-degree gas observed in supernova remnants (e.g., Cioffi, 1990), or the accretion disks around neutron stars and bla ...
... Astrophysical X-ray emission is generally found to originate from hot collisional plasmas, such as the million-degree gas found in the solar corona (e.g., Foukal, 1990), the 100million-degree gas observed in supernova remnants (e.g., Cioffi, 1990), or the accretion disks around neutron stars and bla ...
McConnell XGPolarimetry SSE
... direction and the direction to the observer. For gamma-ray bursts, for example, the preferred direction may be the axis of the jet; in pulsars, it may be the magnetic axis; near black holes or neutron stars, it may be the strong gravitational field; for the nonthermal emission in solar flares, it is ...
... direction and the direction to the observer. For gamma-ray bursts, for example, the preferred direction may be the axis of the jet; in pulsars, it may be the magnetic axis; near black holes or neutron stars, it may be the strong gravitational field; for the nonthermal emission in solar flares, it is ...
UvA-DARE (Digital Academic Repository)
... A nn often used diagnostic tool in pulsar physics is the l o g o versus l o g P diagram. As a demonstration,, in figure 1.1 we plotted the derived magnetic field strength versus spin periods forr a large number of pulsars. The diagram was adopted from Van den Heuvel (1991). 'Ordinary' pulsarss are l ...
... A nn often used diagnostic tool in pulsar physics is the l o g o versus l o g P diagram. As a demonstration,, in figure 1.1 we plotted the derived magnetic field strength versus spin periods forr a large number of pulsars. The diagram was adopted from Van den Heuvel (1991). 'Ordinary' pulsarss are l ...
Neutron Stars and Black Holes
... 17. What observational evidence do we have that stellar death black holes really exist? a. Hollowed-out green spheres are sucking up matter in star forming regions and emitting gamma rays. b. Some X-ray binaries have an unseen object with masses greater than 3 solar masses. c. Some X-ray binaries em ...
... 17. What observational evidence do we have that stellar death black holes really exist? a. Hollowed-out green spheres are sucking up matter in star forming regions and emitting gamma rays. b. Some X-ray binaries have an unseen object with masses greater than 3 solar masses. c. Some X-ray binaries em ...
Hunting for Orphaned Central Compact Objects among Radio Pulsars
... rate measurements of the three CCOs with X-ray pulsations indicate surface dipole fields much weaker than those of typical young pulsars. To investigate if CCOs and known radio pulsars are objects at different evolutionary stages, we carried out a census of all weak-field (< 1011 G) isolated radio p ...
... rate measurements of the three CCOs with X-ray pulsations indicate surface dipole fields much weaker than those of typical young pulsars. To investigate if CCOs and known radio pulsars are objects at different evolutionary stages, we carried out a census of all weak-field (< 1011 G) isolated radio p ...
L95 IRON-RICH EJECTA IN THE SUPERNOVA
... that appear here, were extracted. Likewise two spectra of the core X-ray emission (again outer and inner) were extracted. Background-subtracted count rates are given in Table 1. Background represented less than 0.5% of the source count rate in the 0.2–5 keV band as taken from a 1⬘–2⬘ annulus outside ...
... that appear here, were extracted. Likewise two spectra of the core X-ray emission (again outer and inner) were extracted. Background-subtracted count rates are given in Table 1. Background represented less than 0.5% of the source count rate in the 0.2–5 keV band as taken from a 1⬘–2⬘ annulus outside ...
end-of-summer report
... activity in stars differs depending on which energy band is observed. Thus far, stellar UV emission has proven to be the most convenient medium for detecting magnetic flux variability over long time scales. Simply put, ground based telescopes can easily detect the UV band from stars and this allows ...
... activity in stars differs depending on which energy band is observed. Thus far, stellar UV emission has proven to be the most convenient medium for detecting magnetic flux variability over long time scales. Simply put, ground based telescopes can easily detect the UV band from stars and this allows ...
Lyman-α observations of astrospheres
... respectively). The other two targets are unresolved binaries (70 Oph AB and 36 Oph AB) with rotational periods in the range 19.7–22.9 days and measured mass-loss rates only for the binary systems rather than for the individual stars. The third group of G–K dwarf stars consists of π 1 UMa (Wood et al ...
... respectively). The other two targets are unresolved binaries (70 Oph AB and 36 Oph AB) with rotational periods in the range 19.7–22.9 days and measured mass-loss rates only for the binary systems rather than for the individual stars. The third group of G–K dwarf stars consists of π 1 UMa (Wood et al ...
Recipes for ULX formation: necessary ingredients and garnishments
... a compelling need to invoke intermediate-mass BHs in ULXs, and that the upper mass limit is likely to be somewhere between 50 and 200M . Correspondingly, if dynamical collapse and merger processes are still needed to form a very massive stellar progenitor (> 100M ), clusters as small as ∼ 104 M m ...
... a compelling need to invoke intermediate-mass BHs in ULXs, and that the upper mass limit is likely to be somewhere between 50 and 200M . Correspondingly, if dynamical collapse and merger processes are still needed to form a very massive stellar progenitor (> 100M ), clusters as small as ∼ 104 M m ...
SGR and AXP – are they magnetars?
... A radiative model for the soft gamma repeaters and the energetic 1979 March 5 burst is presented. We identify the sources of these bursts with neutron stars the external magnetic fields of which are much stronger than those of ordinary pulsars. Several independent arguments point to a neutron star w ...
... A radiative model for the soft gamma repeaters and the energetic 1979 March 5 burst is presented. We identify the sources of these bursts with neutron stars the external magnetic fields of which are much stronger than those of ordinary pulsars. Several independent arguments point to a neutron star w ...
the obscuration in liners - Instituto de Astronomía
... claimed (González-Martı́n et al. 2009b) that a high percentage of them are obscured sources. Mid-infrared high spatial resolution data will bring us the oportunity to study the obscuration of these intringuing sources. However, these observations have been challenging due to the faintness of the so ...
... claimed (González-Martı́n et al. 2009b) that a high percentage of them are obscured sources. Mid-infrared high spatial resolution data will bring us the oportunity to study the obscuration of these intringuing sources. However, these observations have been challenging due to the faintness of the so ...
A systematic study of X-ray variability in the ROSAT all
... The ROSAT X-ray observatory, launched in 1990, carried out an all-sky survey during its first six months of operations. This first X-ray imaging all-sky survey tremendously increased the number of X-ray sources known at the time. Variability is known to be one of the key properties of the X-ray sky. ...
... The ROSAT X-ray observatory, launched in 1990, carried out an all-sky survey during its first six months of operations. This first X-ray imaging all-sky survey tremendously increased the number of X-ray sources known at the time. Variability is known to be one of the key properties of the X-ray sky. ...
Neutron Star
... around the pulsar, they cause it to wobble around, resulting in slight changes of the ...
... around the pulsar, they cause it to wobble around, resulting in slight changes of the ...
The spin and orbit of the newly discovered pulsar IGR J17480-2446
... 10–100 ms. Pulsations were detected in all observations performed by RXTE, as well as in two out of the three Swift observations performed in WT mode presented here. The pulsed fraction is observed to drastically change on a timescale of 1 d, after the RXTE observation performed on MJD 55 482. Whil ...
... 10–100 ms. Pulsations were detected in all observations performed by RXTE, as well as in two out of the three Swift observations performed in WT mode presented here. The pulsed fraction is observed to drastically change on a timescale of 1 d, after the RXTE observation performed on MJD 55 482. Whil ...
The Milky Way - National Tsing Hua University
... around the pulsar, they cause it to wobble around, resulting in slight changes of the ...
... around the pulsar, they cause it to wobble around, resulting in slight changes of the ...
X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy is the space science related to a type of space telescope that can see farther than standard light-absorption telescopes, such as the Mauna Kea Observatories, via x-ray radiation.X-ray emission is expected from astronomical objects that contain extremely hot gasses at temperatures from about a million kelvin (K) to hundreds of millions of kelvin (MK). Although X-rays have been observed emanating from the Sun since the 1940s, the discovery in 1962 of the first cosmic X-ray source was a surprise. This source is called Scorpius X-1 (Sco X-1), the first X-ray source found in the constellation Scorpius. The X-ray emission of Scorpius X-1 is 10,000 times greater than its visual emission, whereas that of the Sun is about a million times less. In addition, the energy output in X-rays is 100,000 times greater than the total emission of the Sun in all wavelengths. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002. It is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects.Many thousands of X-ray sources are known. In addition, the space between galaxies in galaxy clusters is filled with a very hot, but very dilute gas at a temperature between 10 and 100 megakelvins (MK). The total amount of hot gas is five to ten times the total mass in the visible galaxies.