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Using the Urumqi 25m radio telescope, sources from the first three-month Fermi-LAT detected AGN catalog with declination >0 were observed in 2009 at 4.8 GHz. The radio flux density appears to correlate with the gamma-ray intensity.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Xiang Liu , Hua-Gang Song , Jun Liu , Zhen Ding , Nicola Marchili , Thomas P. Krichbaum , Lars Fuhrmann , Anton Zensus , Tao An

With the uGMRT having unprecedented sensitivity and unique capability of providing instantaneous frequency coverage of 250$-$1460 MHz, we studied ${\rm FRB}\,20180916$B over four months sampling during its active phase. We report the…

High Energy Astrophysical Phenomena · Physics 2026-04-06 Siddhartha Bhattacharyya , Jayanta Roy , Apurba Bera

A promising approach to detect high-energy tau neutrinos is through the measurement of impulsive radio emission from horizontal air showers initiated in the Earth's atmosphere. Observations at frequencies between 30 and 80 MHz seem…

Instrumentation and Methods for Astrophysics · Physics 2024-10-31 Tim Huege , Oliver Krömer

We explore the radio emission of JWST-selected Broad Line AGN (BLAGN, or type 1) in the GOODS-N field. We use deep radio data at different frequencies (144\,MHz, 1.5\,GHz, 3\,GHz, 5.5\,GHz, 10\,GHz), and we find that none of the {37}…

We present the results of commissioning observations for a new digital beamforming back end for the Focal plane L-band Array for the Robert C. Byrd Green Bank Telescope (FLAG), a cryogenically cooled Phased Array Feed (PAF) with the lowest…

We present a case for significantly enhancing the utility and efficiency of the ngEHT by incorporating an additional 86 GHz observing band. In contrast to 230 or 345 GHz, weather conditions at the ngEHT sites are reliably good enough for 86…

The National Science Foundation (NSF) Astronomy Division's Portfolio Review of 2012 is no longer relevant to the Green Bank Telescope (GBT) of 2017 for two principal reasons, one instrumental and the other astrophysical: 1) The GBT has…

Instrumentation and Methods for Astrophysics · Physics 2016-10-10 Felix J. Lockman , Ryan Lynch , David T. Frayer , Brian D. Mason , Scott M. Ransom

The Gamma Ray Burst (GRB) 180720B is one of the brightest events detected by the Fermi satellite and the first GRB detected by the H.E.S.S. telescope above 100 GeV. We analyse the Fermi (GBM and LAT) and Swift (XRT and BAT) data and…

High Energy Astrophysical Phenomena · Physics 2020-04-22 M. Ronchi , F. Fumagalli , M. E. Ravasio , G. Oganesyan , M. Toffano , O. S. Salafia , L. Nava , S. Ascenzi , G. Ghirlanda , G. Ghisellini

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) , composed of two small satellites, is a new mission to monitor the Gamma-Ray Bursts (GRBs) coincident with Gravitational Wave (GW) events with a FOV of…

Instrumentation and Detectors · Physics 2021-12-22 Da-Li Zhang , Xin-Qiao Li , Shao-Lin Xiong , Wen-xi Peng , Fan-Zhang , Yanguo-Li , Zheng-Hua An , Yan-Bing Xu , Xi-Lei Sun , Yue Zhu

Gamma rays at rest frame energies as high as 90 GeV have been reported from gamma-ray bursts (GRBs) by the Fermi Large Area Telescope (LAT). There is considerable hope that a confirmed GRB detection will be possible with the upcoming…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Rudy C. Gilmore , Aurelien Bouvier , Valerie Connaughton , Adam Goldstein , Nepomuk Otte , Joel R. Primack , David A. Williams

Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial radionuclides measured during airborne surveys. The frontiers of radiometric measurements with UAV require light and accurate altimeters flying…

The Haystack 37-meter telescope was used in a pilot project in May 1995 to observe GRB error boxes at 23~GHz. Seven BATSE error boxes and two IPN arcs were scanned by driving the beam of the telescope rapidly across their area. For the…

Jets of high-redshift active galactic nuclei (AGNs) can be used to directly probe the activity of the black holes in the early Universe. Radio sources with jets misaligned with respect to the line of sight are expected to dominate the…

High Energy Astrophysical Phenomena · Physics 2021-08-18 Yingkang Zhang , Tao An , Sándor Frey , Xiaolong Yang , Máté Krezinger , Oleg Titov , Alexey Melnikov , Pablo de Vicente , Fengchun Shu , Ailing Wang

We present our optical photometric and spectroscopical observations of GRB 140629A. A redshift of $z=2.275\pm0.043$ is measured through the metal absorption lines in our spectroscopic data. Using our photometric data and multiple…

High Energy Astrophysical Phenomena · Physics 2018-06-13 Li-Ping Xin , Shu-Qing Zhong , En-Wei Liang , Jing Wang , Hao Liu , Tian-Meng Zhang , Xiao-Li Huang , Hua-Li Li , Yu-Lei Qiu , Xu-Hui Han , Jian-Yan Wei

We have used the 610 MHz receivers of the Giant Metrewave Radio Telescope (GMRT) to detect associated HI 21cm absorption from the $z = 1.2230$ blazar TXS1954+513. The GMRT HI 21cm absorption is likely to arise against either the…

Astrophysics of Galaxies · Physics 2017-01-11 J. N. H. S. Aditya , Nissim Kanekar , J. Xavier Prochaska , Brandon Day , Paul Lynam , Jocelyn Cruz

The F-GAMMA-project is the coordinated effort of several observatories to understand the AGN phenomenon and specifically blazars via multi-frequency monitoring in collaboration with the {\sl Fermi}-GST satellite since January 2007. The core…

We correlate the positions of radio galaxies in the FIRST survey with the CMB lensing convergence estimated from the Atacama Cosmology Telescope over 470 square degrees to determine the bias of these galaxies. We remove optically…

After almost 4 years of operation, the two instruments onboard the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts with high energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Carl W. Akerlof , WeiKang Zheng

We present a partial-sky survey of the radio continuum at 2.3 GHz within the scope of the Galactic Emission Mapping (GEM) project, an observational program conceived and developed to reveal the large-scale properties of Galactic synchrotron…

On September 21 at 18950.56 SOD (05:15:50.56) UT the FREGATE gamma-ray instrument on the High Energy Transient Explorer (HETE) detected a bright gamma-ray burst (GRB). The burst was also seen by the X-detector on the WXM X-ray instrument…