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.

scholarly journals Detection of a flaring blazar coincident with an IceCube high-energy neutrino

2019 ◽  
Vol 207 ◽  
pp. 02001
Author(s):  
Anna Franckowiak
Keyword(s):  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Neutrino Flux ◽  
High Energy ◽  
Spectral Energy ◽  
Large Area ◽  
High Energy Neutrino ◽  
Energy Neutrino ◽  
Radio Wavelength ◽  
First Time

In September 22, 2017, IceCube released a public alert announcing the detection of a 290 TeV neutrino track event with an angular uncertainty of one square degree (90% containment). A multi-messenger follow-up campaign was initiated resulting in the detection of a GeV gamma-ray flare by the Fermi Large Area Telescope positionally consistent with the location of the known Bl Lac object, TXS 0506+056 , located only 0.1 degrees from the best-fit neutrino position. The probability of finding a GeV gamma-ray flare in coincidence with a high-energy neutrino event assuming a correlation of the neutrino flux with the gamma-ray energy flux in the energy band between 1 and 100 GeV was calculated to be 3σ (after trials correction). Following the detection of the flaring blazar the imaging air Cherenkov telescope MAGIC detected the source for the first time in the > 100 GeV gamma-ray band. The activity of the source was confirmed in X-ray, optical and radio wavelength. Several groups have developed lepto-hadronic models which succeed to explain the multi-messenger spectral energy distribution.

scholarly journals GRB 171205A/SN 2017iuk: A local low-luminosity gamma-ray burst

2018 ◽  
Vol 619 ◽  
pp. A66 ◽  
Author(s):  
V. D’Elia ◽  
S. Campana ◽  
A. D’Aì ◽  
M. De Pasquale ◽  
S. W. K. Emery ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Host Galaxy ◽  
Isotropic Energy ◽  
Optical Telescope ◽  
X Ray ◽  
Hydrogen Column Density ◽  
Peak Energy ◽  
First Time

Context. Gamma-ray bursts (GRBs) occurring in the local Universe constitute an interesting sub-class of the GRB family, since their luminosity is on average lower than that of their cosmological analogs. Attempts to understand in a global way this peculiar behaviour is still not possible, since the sample of low redshift GRBs is small, and the properties of individual objects are too different from each other. In addition, their closeness (and consequently high fluxes) make these sources ideal targets for extensive follow-up even with small telescopes, considering also that these GRBs are conclusively associated with supernova (SN) explosions. Aims. We aim to contribute to the study of local bursts by reporting the case of GRB 171205A. This source was discovered by Swift Burst Alert Telescope (BAT) on 2017, December 5 and soon associated with a low redshift host galaxy (z = 0.037), and an emerging SN (SN 2017iuk). Methods. We analyzed the full Swift dataset, comprising the UV-Optical Telescope (UVOT), X-ray Telescope (XRT) and BAT data. In addition, we employed the Konus-Wind high energy data as a valuable extension at γ-ray energies. Results. The photometric SN signature is clearly visible in the UVOT u, b and ν filters. The maximum emission is reached at ∼13 (rest frame) days, and the whole bump resembles that of SN 2006aj, but lower in magnitude and with a shift in time of +2 d. A prebump in the ν-band is also clearly visible, and this is the first time that such a feature is not observed achromatically in GRB–SNe. Its physical origin cannot be easily explained. The X-ray spectrum shows an intrinsic Hydrogen column density NH,int = 7.4+4.1−3.6 × 1020 cm−2, which is at the low end of the N H, int, even considering just low redshift GRBs. The spectrum also features a thermal component, which is quite common in GRBs associated with SNe, but whose origin is still a matter of debate. Finally, the isotropic energy in the γ-ray band, Eiso = 2.18+0.63−5.0 × 1049 erg, is lower than those of cosmological GRBs. Combining this value with the peak energy in the same band, Ep = 125+141−37 keV, implies that GRB 171205A is an outlier of the Amati relation, as are some other low redshift GRBs, and its emission mechanism should be different from that of canonical, farther away GRBs.

scholarly journals Gamma-ray follow-up studies onηCarinae

2012 ◽  
Vol 544 ◽  
pp. A98 ◽  
Author(s):  
K. Reitberger ◽  
O. Reimer ◽  
A. Reimer ◽  
M. Werner ◽  
K. Egberts ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Follow Up Studies

scholarly journals Searching for Gamma-Ray Millisecond Pulsars: Selection of Candidates Revisited

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 31
Author(s):  
Xuejie Dai ◽  
Zhongxiang Wang ◽  
Jithesh Vadakkumthani
Keyword(s):  
Point Source ◽  
Gamma Ray ◽  
Previous Analysis ◽  
Test Statistic ◽  
Large Area ◽  
Millisecond Pulsars ◽  
Multi Wavelength ◽  
Γ Ray ◽  
Available Information ◽  
Selection Of

We are starting a project to find γ -ray millisecond pulsars (MSPs) among the unidentified sources detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope (Fermi), by radio observations. The selection of good candidates from analysis of the LAT data is an important part of the project. Given that there is more than 10 years worth of LAT data and the advent of the newly released LAT 8-year point source list (FL8Y), we have conducted a selection analysis, on the basis of our previous analysis, and report the results here. Setting the requirements for the unidentified sources in FL8Y of Galactic latitudes | b | > 5 ∘ and curvature significances >3 σ , there are 202 sources with detection signficances >6 σ . We select 57 relatively bright ones (detection significances >15 σ ) and analyze their 10.2 years of LAT data. Their variability is checked to exclude variable sources (likely blazars), test statistic maps are constructed to avoid contaminated sources, and curvature significances are re-obtained and compared to their γ -ray spectra to exclude non-significant sources. In the end, 48 candidates are found. Based on the available information, mostly from multi-wavelength studies, we discuss the possible nature of several of the candidates. Most of these candidates are currently being observed with the 65-meter Shanghai Tian Ma Radio Telescope.

scholarly journals Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622

2010 ◽  
Vol 525 ◽  
pp. A45 ◽  
Author(s):  
◽  
F. Acero ◽  
F. Aharonian ◽  
A. G. Akhperjanian ◽  
G. Anton ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Follow Up Studies

scholarly journals Gamma-ray follow-up studies on η Carinae

2012 ◽  
Author(s):  
K. Reitberger ◽  
O. Reimer ◽  
A. Reimer ◽  
M. Werner ◽  
K. Egberts ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Follow Up Studies

scholarly journals Rapid-response radio observations of short GRB 181123B with the Australia Telescope Compact Array

2021 ◽  
Author(s):  
G E Anderson ◽  
M E Bell ◽  
J Stevens ◽  
M D Aksulu ◽  
J C A Miller-Jones ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Early Time ◽  
Rapid Response ◽  
Radio Flux ◽  
Radio Observations ◽  
Forward Shock ◽  
Radio Band ◽  
Short Grbs ◽  
Compact Array

Abstract We introduce the Australia Telescope Compact Array (ATCA) rapid-response mode by presenting the first successful trigger on the short-duration gamma-ray burst (GRB) 181123B. Early-time radio observations of short GRBs may provide vital insights into the radio afterglow properties of Advanced LIGO- and Virgo-detected gravitational wave events, which will in turn inform follow-up strategies to search for counterparts within their large positional uncertainties. The ATCA was on target within 12.6 hr post-burst, when the source had risen above the horizon. While no radio afterglow was detected during the 8.3 hr observation, we obtained force-fitted flux densities of 7 ± 12 and 15 ± 11μJy at 5.5 and 9 GHz, respectively. Afterglow modelling of GRB 181123B showed that the addition of the ATCA force-fitted radio flux densities to the Swift X-ray Telescope detections provided more stringent constraints on the fraction of thermal energy in the electrons (log $\epsilon _e = -0.75^{+0.39}_{-0.40}$ rather than log $\epsilon _e = -1.13^{+0.82}_{-1.2}$ derived without the inclusion of the ATCA values), which is consistent with the range of typical εe derived from GRB afterglow modelling. This allowed us to predict that the forward shock may have peaked in the radio band ∼10 days post-burst, producing detectable radio emission ≳ 3 − 4 days post-burst. Overall, we demonstrate the potential for extremely rapid radio follow-up of transients and the importance of triggered radio observations for constraining GRB blast wave properties, regardless of whether there is a detection, via the inclusion of force-fitted radio flux densities in afterglow modelling efforts.

A Population of Gamma-Ray Millisecond Pulsars Seen with the Fermi Large Area Telescope

Science ◽  
2009 ◽  
Vol 325 (5942) ◽  
pp. 848-852 ◽  
Author(s):  
A. A. Abdo ◽  
M. Ackermann ◽  
M. Ajello ◽  
W. B. Atwood ◽  
M. Axelsson ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Large Area ◽  
Millisecond Pulsars

Male Admissions to the English Special Hospitals — 1961–1965: A Demographic Survey

1980 ◽  
Vol 136 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Gavin Tennent ◽  
Elizabeth Parker ◽  
Patrick G. McGrath ◽  
David Street
Keyword(s):  
The Social ◽  
Demographic Survey ◽  
Follow Up Studies ◽  
Long Term Follow Up ◽  
Male Patients ◽  
Special Hospitals ◽  
First Time ◽  
Admission Group

SummaryThe social, criminal and psychiatric backgrounds of 878 male patients admitted for the first time to the three English Special Hospitals during the years 1961–1965 are examined and the implications of differences between them for research discussed. It is noted that only 35 per cent of the admission group have been discharged within a four year period. The need for long term follow-up studies is stressed.

scholarly journals The Einstein@Home Survey for Gamma-ray Pulsars

2017 ◽  
Vol 13 (S337) ◽  
pp. 21-24
Author(s):  
Colin J. Clark ◽  
Jason Wu ◽  
Holger J. Pletsch ◽  
Lucas Guillemot
Keyword(s):  
Large Scale ◽  
Gamma Ray ◽  
Large Fraction ◽  
Computing System ◽  
Data Reconstruction ◽  
Volunteer Computing ◽  
Radio Observations ◽  
Large Area ◽  
Space Telescope ◽  
Blind Search

AbstractSince the launch of the Fermi Gamma-ray Space Telescope in 2008, the onboard Large Area Telescope (LAT) has detected gamma-ray pulsations from more than 200 pulsars. A large fraction of these remain undetected in radio observations, and could only be found by directly searching the LAT data for pulsations. However, the sensitivity of such “blind” searches is limited by the sparse photon data and vast computational requirements. In this contribution we present the latest large-scale blind-search survey for gamma-ray pulsars, which ran on the distributed volunteer computing system, Einstein@Home, and discovered 19 new gamma-ray pulsars. We explain how recent improvements to search techniques and LAT data reconstruction have boosted the sensitivity of blind searches, and present highlights from the survey’s discoveries. These include: two glitching pulsars; the youngest known radio-quiet gamma-ray pulsar; and two isolated millisecond pulsars (MSPs), one of which is the only known radio-quiet rotationally powered MSP.

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