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11. AMI 15.7GHz GRB catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/473/1512
Title:
AMI 15.7GHz GRB catalogue
Short Name:
J/MNRAS/473/1512
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target within 2-min, scheduling later start times if the source is below the horizon. Further AMI observations are manually scheduled for several days following the trigger. The AMI GRB programme probes the early-time (<1d) radio properties of GRBs, and has obtained some of the earliest radio detections (GRB 130427A at 0.36 and GRB 130907A at 0.51d post-burst). As all Swift GRBs visible to AMI are observed, this catalogue provides the first representative sample of GRB radio properties, unbiased by multiwavelength selection criteria. We report the detection of six GRB radio afterglows that were not previously detected by other radio telescopes, increasing the rate of radio detections by 50 per cent over an 18-month period. The AMI catalogue implies a Swift GRB radio detection rate of >~15 per cent, down to ~0.2mJy/beam. However, scaling this by the fraction of GRBs AMI would have detected in the Chandra & Frail (2012, Cat. J/ApJ/746/156) sample (all radio-observed GRBs between 1997 and 2011), it is possible ~44-56 per cent of Swift GRBs are radio bright, down to ~0.1-0.15mJy/beam. This increase from the Chandra & Frail (2012, Cat. J/ApJ/746/156) rate (~30 per cent) is likely due to the AMI rapid-response mode, which allows observations to begin while the reverse-shock is contributing to the radio afterglow.
12. Analysis of Fermi GRB data. IV. Spectral lags
ID:
ivo://CDS.VizieR/J/ApJ/865/153
Title:
Analysis of Fermi GRB data. IV. Spectral lags
Short Name:
J/ApJ/865/153
Date:
21 Oct 2021
Publisher:
CDS
Description:
The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts observed by the Fermi Gamma-ray Burst Monitor (GBM) telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S; 64/92), H2S-dominated-tracking pulses (21/92), and other tracking pulses (7/92). We focus on the relationship between spectral evolution and spectral lags of H2S and H2S-dominated-tracking pulses. The main trend of spectral evolution (lag behavior) is estimated with logE_p_{propto}k_E_log(t+t_0_) (^{tau}{propto}k_^{tau}logE), where E_p_ is the peak photon energy in the radiation spectrum, t+t_0_ is the observer time relative to the beginning of pulse -t0, and ^{tau} is the spectral lag of photons with energy E with respect to the energy band 8-25keV. For H2S and H2S-dominated-tracking pulses, a weak correlation between k_^{tau}/W and kE is found, where W is the pulse width. We also study the spectral lag behavior with peak time t_pE_ of pulses for 30 well-shaped pulses and estimate the main trend of the spectral lag behavior with logt_pE_{propto}k_tp_logE. It is found that k_tp_ is correlated with kE. We perform simulations under a phenomenological model of spectral evolution, and find that these correlations are reproduced. We then conclude that spectral lags are closely related to spectral evolution within the pulse. The most natural explanation of these observations is that the emission is from the electrons in the same fluid unit at an emission site moving away from the central engine, as expected in the models invoking magnetic dissipation in a moderately high-{sigma} outflow.
13. Analysis of {gamma}-ray bursts
ID:
ivo://CDS.VizieR/J/MNRAS/418/2202
Title:
Analysis of {gamma}-ray bursts
Short Name:
J/MNRAS/418/2202
Date:
21 Oct 2021
Publisher:
CDS
Description:
To find out the astrophysical processes responsible for gamma-ray burst (GRB), it is crucial to discover and understand the relations between their observational properties. This work was performed in the GRB rest frames using a sample of 62 long Swift GRBs with known redshifts. Following the earlier analysis of the correlation between afterglow luminosity (L^*^a) and break time (T^*^a), we extend it to correlations between the afterglow and the prompt emission GRB physical parameters.
14. Antimatter sources E flux sensitivity
ID:
ivo://CDS.VizieR/J/other/PhRvD/103.H3016
Title:
Antimatter sources E flux sensitivity
Short Name:
J/other/PhRvD/10
Date:
22 Feb 2022
Publisher:
CDS
Description:
It is generally taken for granted that our Universe is free of antimatter objects and domains. This certitude has recently been challenged by the possible detection of anti-helium nuclei by AMS-02. Should the observation be confirmed, the existence of nearby antistars would make a plausible hypothesis to explain the origin of the antinuclei. In this paper we use the 10-years F Large Area Telescope (LAT) gamma-ray source catalog to set constraints on the abundance of antistars around the Sun. We identify in the catalog 14 antistar candidates not associated with any objects belonging to established gamma-ray source classes and with a spectrum compatible with baryon-antibaryon annihilation. We use them along with an estimate of the LAT sensitivity to antistars to set upper limits on the local antistar fraction f_bar*_ with respect to normal stars. We provide parametric limits as a function of the closest antistar mass, velocity, and surrounding matter density. We also employ a novel Monte~Carlo method to set limits for a few hypotheses about the antistar population. For a population with properties equivalent to those of regular stars concentrated in the Galactic disk we obtain f_bar*_<2.5x10^-6^ at 95% confidence level, which is 20 times more constraining than limits previously available. For a primordial population of antistars distributed in the Galactic halo we obtain new local upper limits which decrease as a function of antistar mass M from f_bar*_<0.2 at 95% confidence level for M=1M_{sun}_ to f_bar*_<1.6x10^-4^ at 95% confidence level for M=10M_{sun}_. By combining these limits with existing microlensing constraints for lighter objects in the Magellanic clouds, we infer that a primordial population of halo antistars must have a density lower than O (10^-5^pc^-3^) to O (10^-2^pc^-3^) depending on their masses. Our limits can constrain models for the origin and propagation of antinuclei in cosmic rays.
15. Application of the D^3^PO algorithm
ID:
ivo://CDS.VizieR/J/A+A/581/A126
Title:
Application of the D^3^PO algorithm
Short Name:
J/A+A/581/A126
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the 6.5yr all-sky data from the Fermi LAT restricted to gamma-ray photons with energies between 0.6-307.2GeV. We present a non-parametric reconstruction of the diffuse photon flux up to several hundred GeV, its all-sky spectral index map, and its angular power spectrum. We decompose the diffuse emission into a cloud-like abd a bubble-like component and analyze their spectra. Additionally, we wrote up a catalog of source candidates that includes 3106 sources. For each source we report the location in the sky, flux, spectral index, and possible associations with sources from the second and third Fermi source catalog.
16. A search for progenitors of short GRBs
ID:
ivo://CDS.VizieR/J/ApJ/777/132
Title:
A search for progenitors of short GRBs
Short Name:
J/ApJ/777/132
Date:
21 Oct 2021
Publisher:
CDS
Description:
We searched for periodic and quasi-periodic signals in the prompt emission of a sample of 44 bright short gamma-ray bursts (GRBs) detected with Fermi/GBM, Swift/BAT, and CGRO/BATSE. The aim was to look for the observational signature of quasi-periodic jet precession, which is expected from black hole (BH)-neutron star (NS) mergers, but not from double NS systems. Thus, this kind of search holds the key to identifying the progenitor systems of short GRBs and, in the interim before gravitational wave detectors become on-lines, represents the only direct way to constrain the progenitors. We tailored our search to the nature of the expected signal by properly stretching the observed light curves by an increasing factor with time, after calibrating the technique with synthetic curves. None of our GRBs showed evidence for periodic or quasi-periodic signals. In particular, for the seven unambiguously short GRBs with the best signal-to-noise ratios, we obtained significant upper limits to the amplitude of the possible oscillations. This result suggests that BH-NS systems do not dominate the population of short GRB progenitors, as described by the kinematic model of Stone et al. (2013PhRvD..87h4053S).
17. Associations to 1FGL sources
ID:
ivo://CDS.VizieR/J/ApJ/753/83
Title:
Associations to 1FGL sources
Short Name:
J/ApJ/753/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Fermi Large Area Telescope (LAT) First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of {gamma}-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of source types known to emit {gamma} rays, 630 of these sources are "unassociated" (i.e., have no obvious counterparts at other wavelengths). Here, we employ two statistical analyses of the primary {gamma}-ray characteristics for these unassociated sources in an effort to correlate their {gamma}-ray properties with the active galactic nucleus (AGN) and pulsar populations in 1FGL. Based on the correlation results, we classify 221 AGN-like and 134 pulsar-like sources in the 1FGL unassociated sources. The results of these source "classifications" appear to match the expected source distributions, especially at high Galactic latitudes. While useful for planning future multiwavelength follow-up observations, these analyses use limited inputs, and their predictions should not be considered equivalent to "probable source classes" for these sources. We discuss multiwavelength results and catalog cross-correlations to date, and provide new source associations for 229 Fermi-LAT sources that had no association listed in the 1FGL catalog. By validating the source classifications against these new associations, we find that the new association matches the predicted source class in ~80% of the sources.
18. A survey for H{alpha} pulsar bow shocks
ID:
ivo://CDS.VizieR/J/ApJ/784/154
Title:
A survey for H{alpha} pulsar bow shocks
Short Name:
J/ApJ/784/154
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on a survey for H{alpha} bow shock emission around nearby {gamma}-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around Fermi pulsar PSR J1741-2054, we now report H{alpha} structures around two additional {gamma}-ray pulsars, PSR J2030+4415 and PSR J1509-5850. These are the first known examples of H{alpha} nebulae with pre-ionization halos. With new measurements, we show that a simple analytic model can account for the angular size and flux of the bow shocks' apices. The latter, in particular, provides a new pulsar probe and indicates large moments of inertia and smaller distances than previously assumed in several cases. In particular, we show that the re-measured PSR J0437-4715 shock flux implies I=(1.7+/-0.2)x10^45^/(f_H I_sin i)g cm^2^. We also derive a distance d~0.72 kpc for the {gamma}-ray only pulsar PSR J2030+4415 and revised distances for PSRs J1959+2048 (1.4 kpc) and J2555+6535 (~1 kpc), smaller than the conventional DM-estimated values. Finally, we report upper limits for 94 additional LAT pulsars. An estimate of the survey sensitivity indicates that for a warm neutral medium filling factor {phi}_WNM_~0.3 there should be a total of approximately nine H{alpha} bow shocks in our LAT-targeted survey; given that seven such objects are now known, a much larger {phi}_WNM_ seems problematic.
19. A VLA study of high-redshift GRBs. I. GRB140311A
ID:
ivo://CDS.VizieR/J/ApJ/858/65
Title:
A VLA study of high-redshift GRBs. I. GRB140311A
Short Name:
J/ApJ/858/65
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results from a recently concluded study of GRBs at z>~5 with the Karl G. Jansky Very Large Array (VLA). Spanning 1 to 85.5GHz and 7 epochs from 1.5 to 82.3d, our observations of GRB140311A are the most detailed joint radio and millimeter observations of a GRB afterglow at z>~5 to date. In conjunction with optical/near-IR and X-ray data, the observations can be understood in the framework of radiation from a single blast wave shock with energy E_K,iso_~8.5x10^53^erg expanding into a constant density environment with density, n_0_~8cm^-3^. The X-ray and radio observations require a jet break at t_jet_~0.6d, yielding an opening angle of {theta}_jet_~4{deg} and a beaming-corrected blast wave kinetic energy of E_K_~2.2x10^50^erg. The results from our radio follow-up and multiwavelength modeling lend credence to the hypothesis that detected high-redshift GRBs may be more tightly beamed than events at lower redshift. We do not find compelling evidence for reverse shock emission, which may be related to fast cooling driven by the moderately high circumburst density.
20. BAT AGN spectroscopic survey. XVI. Blazars
ID:
ivo://CDS.VizieR/J/ApJ/881/154
Title:
BAT AGN spectroscopic survey. XVI. Blazars
Short Name:
J/ApJ/881/154
Date:
21 Oct 2021
Publisher:
CDS
Description:
The recently released 105-month Swift-Burst Alert Telescope (BAT) all-sky hard X-ray survey catalog presents an opportunity to study astrophysical objects detected in the deepest look at the entire hard X-ray (14-195keV) sky. Here we report the results of a multifrequency study of 146 blazars from this catalog, quadrupling the number compared to past studies, by utilizing recent data from the Fermi-Large Area Telescope (LAT), Swift-BAT, and archival measurements. In our {gamma}-ray analysis of ~10yr of the LAT data, 101 are found as {gamma}-ray emitters, whereas, 45 remains LAT undetected. We model the broadband spectral energy distributions with a synchrotron-inverse Compton radiative model. On average, BAT detected sources host massive black holes (M_bh_~10^9^M_{sun}_) and luminous accretion disks (L_d_~10^46^erg/s). At high redshifts (z>2), BAT blazars host more powerful jets with luminous accretion disks compared to those detected only with Fermi-LAT. We find good agreement in the black hole masses derived from the single-epoch optical spectroscopic measurements and standard accretion disk modeling approaches. Other physical properties of BAT blazars are similar to those known for Fermi-LAT detected objects.