scholarly journals The Einstein@Home Gamma-ray Pulsar Survey. II. Source Selection, Spectral Analysis, and Multiwavelength Follow-up

2018 ◽  
Vol 854 (2) ◽  
pp. 99 ◽  
Author(s):  
J. Wu ◽  
C. J. Clark ◽  
H. J. Pletsch ◽  
L. Guillemot ◽  
T. J. Johnson ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Gamma Ray ◽  
Source Selection

Gamma-Ray Burst Follow Up Observations with BOOTES in 1998-2000

2003 ◽  
pp. 53-55
Author(s):  
J. M. Castro Cerón ◽  
A. J. Castro-Tirado ◽  
R. Hudec ◽  
J. Soldán ◽  
M. Bernas ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst

scholarly journals Magnetar X-ray emission mechanisms

2012 ◽  
Vol 8 (S291) ◽  
pp. 160-160
Author(s):  
Silvia Zane
Keyword(s):  
Spectral Analysis ◽  
Physical Interpretation ◽  
Spectral Properties ◽  
Gamma Ray ◽  
X Ray ◽  
Spectral Components ◽  
Self Consistent ◽  
Photon Index ◽  
Index 2 ◽  
Surface Fields

AbstractSoft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are peculiar X-ray sources which are believed to be magnetars: ultra-magnetized neutron stars which emission is dominated by surface fields (often in excess of 1E14 G, i.e. well above the QED threshold).Spectral analysis is an important tool in magnetar astrophysics since it can provide key information on the emission mechanisms. The first attempts at modelling the persistent (i.e. outside bursts) soft X-ray (¡10 keV) spectra of AXPs proved that a model consisting of a blackbody (kT 0.3-0.6 keV) plus a power-law (photon index 2-4) could successfully reproduce the observed emission. Moreover, INTEGRAL observations have shown that, while in quiescence, magnetars emit substantial persistent radiation also at higher energies, up to a few hundreds of keV. However, a convincing physical interpretation of the various spectral components is still missing.In this talk I will focus on the interpretation of magnetar spectral properties during quiescence. I will summarise the present status of the art and the currents attempts to model the broadband persistent emission of magnetars (from IR to hard Xrays) within a self consistent, physical scenario.

scholarly journals Optical spectroscopic observations of gamma-ray blazar candidates. VII. Follow-up campaign in the southern hemisphere

2017 ◽  
Vol 362 (12) ◽  
Author(s):  
H. A. Peña-Herazo ◽  
E. J. Marchesini ◽  
N. Álvarez Crespo ◽  
F. Ricci ◽  
F. Massaro ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Gamma Ray ◽  
Spectroscopic Observations

scholarly journals Constraints on the circumburst environments of short gamma-ray bursts

2020 ◽  
Vol 495 (4) ◽  
pp. 4782-4799 ◽  
Author(s):  
Brendan O’Connor ◽  
Paz Beniamini ◽  
Chryssa Kouveliotou
Keyword(s):  
Gamma Ray ◽  
Galactic Halo ◽  
Gamma Ray Bursts ◽  
Light Curves ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Binary Neutron Star ◽  
Range Of Values ◽  
Short Grbs

ABSTRACT Observational follow up of well localized short gamma-ray bursts (SGRBs) has left $20\!-\!30{{\ \rm per\ cent}}$ of the population without a coincident host galaxy association to deep optical and NIR limits (≳26 mag). These SGRBs have been classified as observationally hostless due to their lack of strong host associations. It has been argued that these hostless SGRBs could be an indication of the large distances traversed by the binary neutron star system (due to natal kicks) between its formation and its merger (leading to an SGRB). The distances of GRBs from their host galaxies can be indirectly probed by the surrounding circumburst densities. We show that a lower limit on those densities can be obtained from early afterglow light curves. We find that ${\lesssim}16{{\ \rm per\ cent}}$ of short GRBs in our sample took place at densities ≲10−4 cm−3. These densities represent the expected range of values at distances greater than the host galaxy’s virial radii. We find that out of the five SGRBs in our sample that have been found to be observationally hostless, none are consistent with having occurred beyond the virial radius of their birth galaxies. This implies one of two scenarios. Either these observationally hostless SGRBs occurred outside of the half-light radius of their host galaxy, but well within the galactic halo, or in host galaxies at moderate to high redshifts (z ≳ 2) that were missed by follow-up observations.

scholarly journals Spectral Analysis of Fermi-LAT Gamma-Ray Bursts with Known Redshift and their Potential Use as Cosmological Standard Candles

2019 ◽  
Vol 887 (1) ◽  
pp. 13 ◽  
Author(s):  
F. Fana Dirirsa ◽  
S. Razzaque ◽  
F. Piron ◽  
M. Arimoto ◽  
M. Axelsson ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Potential Use

Identification of Earth Materials by Induced Gamma-Ray Spectral Analysis

10.2118/748-g ◽  
1957 ◽  
Vol 210 (01) ◽  
pp. 89-92 ◽  
Author(s):  
N.L. Muench ◽  
J.S. Osoba
Keyword(s):  
Spectral Analysis ◽  
Gamma Ray

scholarly journals Radio counterparts of gamma-ray pulsars

2012 ◽  
Vol 8 (S291) ◽  
pp. 87-92
Author(s):  
L. Guillemot
Keyword(s):  
Gamma Ray ◽  
Population Studies ◽  
Radio Observations ◽  
Large Area ◽  
Millisecond Pulsars ◽  
Follow Up Studies ◽  
First Time

AbstractObservations of pulsars with the Large Area Telescope (LAT) on the Fermi satellite have revolutionized our view of the gamma-ray pulsar population. For the first time, a large number of young gamma-ray pulsars have been discovered in blind searches of the LAT data. More generally, the LAT has discovered many new gamma-ray sources whose properties suggest that they are powered by unknown pulsars. Radio observations of gamma-ray sources have been key to the success of pulsar studies with the LAT. For example, radio observations of LAT-discovered pulsars provide constraints on the relative beaming fractions, which are crucial for pulsar population studies. Also, radio searches of LAT sources with no known counterparts have been very efficient, with the discovery of over forty millisecond pulsars. I review radio follow-up studies of LAT-discovered pulsars and unidentified sources, and discuss some of the implications of the results.

Directions for Future X-Ray, Optical, and Radio Follow-up Observations of Gamma-Ray Burst Counterparts

1995 ◽  
Vol 452 (1) ◽  
Author(s):  
B. J. McNamara ◽  
T. E. Harrison ◽  
C. L. Williams
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
X Ray

scholarly journals DESAlert: Enabling Real-Time Transient Follow-Up with Dark Energy Survey Data

2016 ◽  
Vol 33 ◽  
Author(s):  
A. Poci ◽  
K. Kuehn ◽  
T. Abbott ◽  
F. B. Abdalla ◽  
S. Allam ◽  
...  
Keyword(s):  
Dark Energy ◽  
Real Time ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
Gamma Ray Burst ◽  
Dark Energy Survey ◽  
Data Products ◽  
Energy Survey

AbstractThe Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.

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