- ID:
- ivo://CDS.VizieR/J/ApJS/233/17
- Title:
- Swift/BAT AGN spectroscopic survey. V. X-ray data
- Short Name:
- J/ApJS/233/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hard X-ray (>=10keV) observations of active galactic nuclei (AGNs) can shed light on some of the most obscured episodes of accretion onto supermassive black holes. The 70-month Swift/BAT all-sky survey, which probes the 14-195keV energy range, has currently detected 838 AGNs. We report here on the broadband X-ray (0.3-150keV) characteristics of these AGNs, obtained by combining XMM-Newton, Swift/XRT, ASCA, Chandra, and Suzaku observations in the soft X-ray band (<=10keV) with 70-month averaged Swift/BAT data. The nonblazar AGNs of our sample are almost equally divided into unobscured (N_H_<10^22^cm^-2^) and obscured (N_H_>=10^22^cm^-2^) AGNs, and their Swift/BAT continuum is systematically steeper than the 0.3-10keV emission, which suggests that the presence of a high-energy cutoff is almost ubiquitous. We discuss the main X-ray spectral parameters obtained, such as the photon index, the reflection parameter, the energy of the cutoff, neutral and ionized absorbers, and the soft excess for both obscured and unobscured AGNs.
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- ID:
- ivo://CDS.VizieR/J/ApJ/681/113
- Title:
- Swift BAT survey of AGNs
- Short Name:
- J/ApJ/681/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the analysis of the first 9 months of data of the Swift BAT (Burst Alert Telescope) survey of AGNs in the 14-195keV band. Using archival X-ray data or follow-up Swift X-ray telescope (XRT) observations, we have identified 129 (103 AGNs) of 130 objects detected at |b|>15{deg} and with significance >4.8{sigma}. One source remains unidentified. These same X-ray data have allowed measurement of the X-ray properties of the objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/58
- Title:
- Swift-BAT survey of AGNs
- Short Name:
- J/ApJ/728/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive and analyze the active galactic nuclei (AGNs) absorption distribution using a complete sample of AGNs detected by Swift-BAT in the first three years of the survey. The fraction of Compton-thick AGNs represents only 4.6% of the total AGN population detected by Swift-BAT. However, we show that once corrected for the bias against the detection of very absorbed sources the real intrinsic fraction of Compton-thick AGNs is 20^+9^_-6_%. We proved for the first time (also in the Burst Alert Telescope (BAT) band) that the anti-correlation of the fraction of absorbed AGNs and luminosity is tightly connected to the different behavior of the X-ray luminosity functions (XLFs) of absorbed and unabsorbed AGNs. This points toward a difference between the two subsamples of objects with absorbed AGNs being, on average, intrinsically less luminous than unobscured ones. Moreover, the XLFs show that the fraction of obscured AGNs might also decrease at very low luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/1843
- Title:
- Swift-BAT survey of Galactic sources
- Short Name:
- J/ApJ/721/1843
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the populations of X-ray sources in the Milky Way in the 15-55keV band using a deep survey with the BAT instrument aboard the Swift observatory. We present the log N-log S distributions of the various source types and we analyze their variability and spectra. For the low-mass X-ray binaries (LMXBs) and the high-mass X-ray binaries (HMXBs), we derive the luminosity functions to a limiting luminosity of L_X_~7x10^34^erg/s. Our results confirm the previously found flattening of the LMXB luminosity function below a luminosity of L_X_~10^37^erg/s. The luminosity function of the HMXBs is found to be significantly flatter in the 15-55keV band than in the 2-10keV band. From the luminosity functions we estimate the ratios of the hard X-ray luminosity from HMXBs to the star formation rate, and the LMXB luminosity to the stellar mass. We use these to estimate the X-ray emissivity in the local universe from X-ray binaries and show that it constitutes only a small fraction of the hard X-ray background.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/L26
- Title:
- Swift/BAT ultra-hard X-ray data from GOALS LIRGs
- Short Name:
- J/ApJ/765/L26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first analysis of the all-sky Swift Burst Alert Telescope (BAT) ultra-hard X-ray (14-195keV) data for a targeted list of objects. We find that the BAT data can be studied at three-times-fainter limits than in previous blind detection catalogs based on prior knowledge of source positions and using smaller energy ranges for source detection. We determine the active galactic nucleus (AGN) fraction in 134 nearby (z<0.05) luminous infrared galaxies (LIRGs) from the GOALS sample. We find that LIRGs have a higher detection frequency than galaxies matched in stellar mass and redshift at 14-195keV and 24-35keV. In agreement with work at other wavelengths, the AGN detection fraction increases strongly at high IR luminosity with half of the high-luminosity LIRGs (50%, 6/12, logL_IR_/L_{sun}_>11.8) detected. The BAT AGN classification shows 97% (37/38) agreement with Chandra and XMM-Newton AGN classification using hardness ratios or detection of an iron K{alpha} line. This confirms our statistical analysis and supports the use of the Swift/BAT all-sky survey to study fainter populations of any category of sources in the ultra-hard X-ray band. BAT AGNs in LIRGs tend to show higher column densities with 40%+/-9% showing 14-195 keV/2-10 keV hardness flux ratios suggestive of high or Compton-thick column densities (logN_H_>24/cm2), compared to only 12%+/-5% of non-LIRG BAT AGNs. We also find that using specific energy ranges of the BAT detector can yield additional sources over total band detections with 24% (5/21) of detections in LIRGs at 24-35keV not detected at 14-195keV.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2210
- Title:
- Swift follow-up of IceCube triggers
- Short Name:
- J/MNRAS/448/2210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Between 2011 March and 2014 August Swift responded to 20 triggers from the IceCube neutrino observatory, observing the IceCube 50 percent confidence error circle in X-rays, typically within 5h of the trigger. No confirmed counterpart has been detected. We describe the Swift follow-up strategy and data analysis and present the results of the campaign. We discuss the challenges of distinguishing the X-ray counterpart to a neutrino trigger from serendipitous uncatalogued X-ray sources in the error circle, and consider the implications of our results for future strategies for multimessenger astronomy, with particular reference to the follow-up of gravitational wave triggers from the advanced-era detectors.
847. SwiftFT catalog
- ID:
- ivo://CDS.VizieR/J/A+A/528/A122
- Title:
- SwiftFT catalog
- Short Name:
- J/A+A/528/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An accurate census of the active galactic nuclei (AGN) is a key step in investigating the nature of the correlation between the growth and evolution of super massive black holes and galaxy evolution. X-ray surveys provide one of the most efficient ways of selecting AGN.
- ID:
- ivo://CDS.VizieR/J/other/ATel/5200
- Title:
- Swift Galactic Plane Survey sourcelist v3
- Short Name:
- J/other/ATel/520
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Swift Galactic Plane Survey team report the detection of 248 point-like X-ray sources (0.3-10keV) in observations covering the final 40% of our survey area (see also 2012ATel.3951....1R and 2012ATel.4318....1R). The listed sources are those we consider to be robust detections at the current time.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/20
- Title:
- Swift GRB catalog with X-ray data
- Short Name:
- J/ApJS/209/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- When a massive star explodes as a gamma-ray burst (GRB), information about the explosion is retained in the properties of the prompt and afterglow emission. We report on new relations between the prompt and X-ray afterglow emission of Swift-detected GRBs found from Burst Alert Telescope (BAT) and X-Ray Telescope data covering 2004 December to 2013 August (754 in total). These relations suggest that the prompt and afterglow emission are closely linked. In particular, we find very strong correlations between the BAT 15-150keV T_90_ and the break times before and after the plateau phase in the 0.3-10keV X-ray afterglow light curves. We also find a strong anticorrelation between the photon index of the GRB prompt emission and the X-ray spectral slope of the afterglow. Moreover, anticorrelations exist between the rest-frame peak energy in the prompt emission E_peak, z_and the X-ray afterglow decay slope during the plateau phase and the break times after the plateau phase. The rest-frame break times before and after the plateau phase are also anticorrelated with the rest-frame 15-150keV luminosity and the isotropic energy during the prompt emission. A principal component analysis suggests that the GRB properties are primarily driven by the luminosity/energy release in the 15-150keV band. Luminosity functions derived at different redshifts from a log N-log S analysis indicate that the density of bright bursts is significantly lower in the local universe than in the universe at z~3, where the density of bright GRBs peaks. Using cluster analysis, we find that the duration of BAT-detected short GRBs is less than 1s.
- ID:
- ivo://CDS.VizieR/J/ApJ/774/157
- Title:
- Swift GRBs with X-ray afterglows and z<9.5
- Short Name:
- J/ApJ/774/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gamma-ray bursts (GRBs), which have been observed up to redshifts z~9.5, can be good probes of the early universe and have the potential to test cosmological models. Dainotti's analysis of GRB Swift afterglow light curves with known redshifts and a definite X-ray plateau shows an anti-correlation between the rest-frame time when the plateau ends (the plateau end time) and the calculated luminosity at that time (or approximately an anti-correlation between plateau duration and luminosity) (Dainotti+ 2008MNRAS.391L..79D, 2010ApJ...722L.215D). Here, we present an update of this correlation with a larger data sample of 101 GRBs with good light curves. Since some of this correlation could result from the redshift dependences of these intrinsic parameters, namely, their cosmological evolution, we use the Efron-Petrosian method to reveal the intrinsic nature of this correlation. We find that a substantial part of the correlation is intrinsic and describe how we recover it and how this can be used to constrain physical models of the plateau emission, the origin of which is still unknown. The present result could help to clarify the debated nature of the plateau emission.
