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131. GRB X-ray afterglows light curves analysis
ID:
ivo://CDS.VizieR/J/ApJ/826/45
Title:
GRB X-ray afterglows light curves analysis
Short Name:
J/ApJ/826/45
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a correlation between the average temporal decay ({alpha}_X,avg,>200s_) and early-time luminosity (L_X,200s_) of X-ray afterglows of gamma-ray bursts as observed by the Swift X-ray Telescope. Both quantities are measured relative to a rest-frame time of 200s after the {gamma}-ray trigger. The luminosity-average decay correlation does not depend on specific temporal behavior and contains one scale-independent quantity minimizing the role of selection effects. This is a complementary correlation to that discovered by Oates et al. (2012MNRAS.426L..86O, 2015MNRAS.453.4121O) in the optical light curves observed by the Swift Ultraviolet Optical Telescope. The correlation indicates that, on average, more luminous X-ray afterglows decay faster than less luminous ones, indicating some relative mechanism for energy dissipation. The X-ray and optical correlations are entirely consistent once corrections are applied and contamination is removed. We explore the possible biases introduced by different light-curve morphologies and observational selection effects, and how either geometrical effects or intrinsic properties of the central engine and jet could explain the observed correlation.
132. GRB X-ray flare temporal and spectral properties
ID:
ivo://CDS.VizieR/J/ApJ/884/59
Title:
GRB X-ray flare temporal and spectral properties
Short Name:
J/ApJ/884/59
Date:
21 Oct 2021
Publisher:
CDS
Description:
Gamma-ray bursts (GRBs) can be divided into three subclasses: X-ray flash (XRF), X-ray rich (XRR), and classical GRB (C-GRB). An X-ray flare is the rebrightening emission shown in the early X-ray afterglow of some GRBs. In this paper, we comprehensively examine the X-ray flare properties among XRF, XRR, and C-GRB subclasses. We utilize the XRF, XRR, and C-GRB subclass samples obtained from the Swift-BAT3 catalog, and the X-ray flare observational properties are collected from Falcone+ (2007ApJ...671.1921F), Chincarini+ (2010MNRAS.406.2113C), and Yi+ (2016, J/ApJS/224/20). We find that XRFs and XRRs have more bright X-ray flares than C-GRBs. The ratio of the X-ray flare fluence to the prompt emission fluence has different distributions between XRF and C-GRB subclasses. The linear correlation between the duration and the peak time of the X-ray flares is also different between XRF and C-GRB subclasses. We are inclined to identify the GRBs with the bright X-ray flares as XRFs or XRRs. We discuss some issues that are related to the XRF/XRR/C-GRB classification. We also caution the selection effects and the instrument bias in our investigation. Large samples are required in the future to further confirm our results.
133. g'r'i'z'JH light curves of GRB 091127
ID:
ivo://CDS.VizieR/J/A+A/535/A57
Title:
g'r'i'z'JH light curves of GRB 091127
Short Name:
J/A+A/535/A57
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using high-quality, broad-band afterglow data for GRB 091127, we investigate the validity of the synchrotron fireball model for gamma-ray bursts, and infer physical parameters of the ultra-relativistic outflow. We used multi-wavelength (NIR to X-ray) follow-up observations obtained with GROND simultaneously in the g'r'i'z' JH filters and the XRT onboard the Swift satellite in the 0.3 to 10keV energy range. The resulting afterglow light curve is of excellent accuracy with relative photometric errors as low as 1%, and the spectral energy distribution is well-sampled over 5 decades in energy. These data present one of the most comprehensive observing campaigns for a single GRB afterglow and allow us to test several proposed emission models and outflow characteristics in unprecedented detail.
134. Hard X-ray catalog of Sagittarius arm
ID:
ivo://CDS.VizieR/J/PAZh/30/589
Title:
Hard X-ray catalog of Sagittarius arm
Short Name:
J/PAZh/30/589
Date:
21 Oct 2021
Publisher:
CDS
Description:
The images of the Sagittarius arm tangent obtained with the IBIS telescope of the INTEGRAL observatory in the energy range 18-120keV during their observations in the spring of 2003 are analyzed.
135. HEGRA AIROBICC gamma radiation above 15 TeV
ID:
ivo://CDS.VizieR/J/A+A/390/39
Title:
HEGRA AIROBICC gamma radiation above 15 TeV
Short Name:
J/A+A/390/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of the search for gamma radiation above 15 TeV, using the AIROBICC air shower detector, from a set of 196 candidate point sources taken from different catalogs. For each object, the equatorial coordinates are provided, together with the number of signal events registered by the detector, the estimated background, the statistical significance of the excess (or defect) of events, the average energy threshold of the observation (in TeV), and the flux upper limit (at 90% confidence level) of gamma rays above this threshold.
136. HESS and Suzaku observations of Vela X
ID:
ivo://CDS.VizieR/J/A+A/627/A100
Title:
HESS and Suzaku observations of Vela X
Short Name:
J/A+A/627/A100
Date:
21 Oct 2021
Publisher:
CDS
Description:
Pulsar Wind Nebulae (PWNe) represent the most prominent population of Galactic very-high-energy gamma-ray sources and are thought to be an efficient source of leptonic cosmic rays. Vela X is a nearby middle-aged PWN, which shows bright X-ray and TeV gamma-ray emission toward an elongated structure called the cocoon. Since TeV emission is likely inverse-Compton emission of electrons, predominantly from interactions with the cosmic microwave background, while X-ray emission is synchrotron radiation of the same electrons, we aim to derive the properties of the relativistic particles and of magnetic fields with minimal modelling. We use data from the Suzaku XIS to derive the spectra from three compact regions in Vela X covering distances from 0.3pc to 4pc from the pulsar along the cocoon. We obtain gamma-ray spectra of the same regions from H.E.S.S. observations and fit a radiative model to the multi-wavelength spectra. The TeV electron spectra and magnetic field strengths are consistent within the uncertainties for the three regions, with energy densities of the order 10^-12^erg/cm^-3^. The data indicate the presence of a cutoff in the electron spectrum at energies of 100TeV and a magnetic field strength of 6G. Constraints on the presence of turbulent magnetic fields are weak. The pressure of TeV electrons and magnetic fields in the cocoon is dynamically negligible, requiring the presence of another dominant pressure component to balance the pulsar wind at the termination shock. Sub-TeV electrons cannot account completely for the missing pressure, that may be provided either by relativistic ions or from mixing of the ejecta with the pulsar wind. The electron spectra are consistent with expectations from transport scenarios dominated either by advection via the reverse shock or by diffusion, but for the latter the role of radiative losses near the termination shock needs to be further investigated in the light of the measured cutoff energies. Constraints on turbulent magnetic fields and the shape of the electron cutoff can be improved by spectral measurements in the energy range >~10keV.
137. H.E.S.S. Galactic Plane Survey
ID:
ivo://CDS.VizieR/J/A+A/612/A1
Title:
H.E.S.S. Galactic Plane Survey
Short Name:
J/A+A/612/A1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) gamma-rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the discovery of 16 new sources of VHE gamma-rays. The High Energy Spectroscopic System (H.E.S.S.) Galactic plane survey (HGPS) was a decade-long observation program carried out by the H.E.S.S. I array of Cherenkov telescopes in Namibia from 2004 to 2013. The observations amount to nearly 2700 h of quality-selected data, covering the Galactic plane at longitudes from l=250{deg} to 65{deg} and latitudes |b|<=3. In addition to the unprecedented spatial coverage, the HGPS also features a relatively high angular resolution (0.08{deg}~5-arcmin mean point spread function 68% containment radius), sensitivity (1.5% Crab flux for point-like sources), and energy range (0.2-100TeV). We constructed a catalog of VHE gamma-ray sources from the HGPS data set with a systematic procedure for both source detection and characterization of morphology and spectrum. We present this likelihood- based method in detail, including the introduction of a model component to account for unresolved, large-scale emission along the Galactic plane. In total, the resulting HGPS catalog contains 78 VHE sources, of which 14 are not reanalyzed here, for example, due to their complex morphology, namely shell-like sources and the Galactic center region. Where possible, we provide a firm identification of the VHE source or plausible associations with sources in other astronomical catalogs. We also studied the characteristics of the VHE sources with source parameter distributions. 16 new sources were previously unknown or unpublished, and we individually discuss their identifications or possible associations. We firmly identified 31 sources as pulsar wind nebulae (PWNe), supernova remnants (SNRs), composite SNRs, or gamma-ray binaries. Among the 47 sources not yet identified, most of them (36) have possible associations with cataloged objects, notably PWNe and energetic pulsars that could power VHE PWNe.
138. HESS Galactic supernova remnants
ID:
ivo://CDS.VizieR/J/A+A/612/A3
Title:
HESS Galactic supernova remnants
Short Name:
J/A+A/612/A3
Date:
21 Oct 2021
Publisher:
CDS
Description:
Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at E~=3x10^15^eV. Our Milky Way galaxy hosts more than 350 SNRs discovered at radio wavelengths and at high energies, of which 220 fall into the H.E.S.S. Galactic Plane Survey (HGPS) region. Of those, only 50 SNRs are coincident with a H.E.S.S source and in 8 cases the very high-energy (VHE) emission is firmly identified as an SNR. The H.E.S.S. GPS provides us with a legacy for SNR population study in VHE {gamma}-rays and we use this rich data set to extract VHE flux upper limits from all undetected SNRs. Overall, the derived flux upper limits are not in contradiction with the canonical CR paradigm. Assuming this paradigm holds true, we can constrain typical ambient density values around shell-type SNRs to n<=7cm^-3^ and electron-to-proton energy fractions above 10TeV to {epsilon}_ep_<=5x10^-3^. Furthermore, comparisons of VHE with radio luminosities in non-interacting SNRs reveal a behaviour that is in agreement with the theory of magnetic field amplification at shell-type SNRs.
139. HESS J1825-137 particle transport
ID:
ivo://CDS.VizieR/J/A+A/621/A116
Title:
HESS J1825-137 particle transport
Short Name:
J/A+A/621/A116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed view of the pulsar wind nebula (PWN) HESS J1825--137. We aim to constrain the mechanisms dominating the particle transport within the nebula, accounting for its anomalously large size and spectral characteristics. The nebula is studied using a deep exposure from over 12 years of H.E.S.S. I operation, together with data from H.E.S.S. II improving the low energy sensitivity. Enhanced energy- dependent morphological and spatially-resolved spectral analyses probe the Very High Energy (VHE, E>0.1TeV) gamma-ray properties of the nebula. The nebula emission is revealed to extend out to 1.5 degrees from the pulsar, ~1.5 times further than previously seen, making HESS J1825-137, with an intrinsic diameter of ~100pc, potentially the largest gamma-ray PWN currently known. Characterisation of the nebula's strongly energy-dependent morphology enables the particle transport mechanisms to be constrained. A dependence of the nebula extent with energy of R{prop.to} E^alpha^ with alpha=-0.29+/-0.04(stat)+/-0.05(sys) disfavours a pure diffusion scenario for particle transport within the nebula. The total gamma-ray flux of the nebula above 1~TeV is found to be (1.12+/-0.03(stat)+/-0.25(sys))x10^-11^cm^-2^s^-1^, corresponding to ~64% of the flux of the Crab Nebula. HESS J1825-137 is a PWN with clear energy-dependent morphology at VHE gamma-ray energies. This source is used as a laboratory to investigate particle transport within middle-aged PWNe. Deep observations of this highly spatially-extended PWN enable a spectral map of the region to be produced, providing insights into the spectral variation within the nebula.
140. HETE Trigger Information
ID:
ivo://CDS.VizieR/J/other/GCN/1070.1
Title:
HETE Trigger Information
Short Name:
J/other/GCN/1070
Date:
21 Oct 2021
Publisher:
CDS
Description:
At 15:54:53.123 UT on 23 June, the HETE FREGATE and WXM instruments detected and localized an intense burst from SGR1806-20, a soft gamma-ray repeater. This event, disseminated in near real time as a GCN Alert (HETE BID_1566; see http://gcn.gsfc.nasa.gov/gcn/hete_grbs.html ), is the second burst localized from this source in the past week. (The first burst was reported in GCN Circular #1068). The coordinates (J2000) of the 23 June burst are: RA=272.1460{deg} (18:08:35.02), DE=-20.3658{deg} (-20:21:56) The error circle for this localization is 6 arcmin in radius. SGR1806-20 lies 3.1arcmin from the HETE position. The burst duration in the 8-40keV band was ~200ms, comprised of two peaks each <100ms in duration. A total of 2250 counts were detected during that interval, corresponding to a fluence of ~4x10^-7^ergs/cm^2^. The peak flux was >6x10^-6^erg/cm^2^/s (i.e. >200Crab-flux). Follow-up observations of this transient are encouraged. Additional information on this burst detection (including light curves), as well as for the HETE mission, will be available at: http://space.mit.edu/HETE/

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