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相关论文: Short timescale variability in the Faint Sky Varia…

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We use archival data from the Phoenix Deep Survey to investigate the variable radio source population above 1mJy/beam at 1.4GHz. Given the similarity of this survey to other such surveys we take the opportunity to investigate the…

星系天体物理 · 物理学 2016-08-03 Paul Hancock , Jason Drury , Martin Bell , Tara Murphy , Bryan Gaensler

We have investigated the time variations in the light curves from a sample of long and short Fermi/GBM Gamma ray bursts (GRBs) using an impartial wavelet analysis. The results indicate that in the source frame, the variability time scales…

高能天体物理现象 · 物理学 2015-06-03 G. A. MacLachlan , A. Shenoy , E. Sonbas , K. S. Dhuga , B. Cobb , T. N. Ukwatta , D. C. Morris , A. Eskandarian , L. C. Maximon , W. C. Parke

We propose a new method for investigating the evolution of the properties of the blazar brightness variability on timescales from a few hours to a few days. Its essence lies in detecting sequentially located time intervals along the entire…

高能天体物理现象 · 物理学 2024-11-28 M. S. Butuzova , V. A. Guseva , M. A. Gorbachev , A. S. Krivenko , S. V. Nazarov

We used the data from the Fermi Gamma-ray Space Telescope to characterise the {\gamma}-ray flux variability of blazars on month-like time scales. Our sample consists of 1120 blazars of which 481 are flat spectrum radio quasars (FSRQs) and…

高能天体物理现象 · 物理学 2020-02-12 Bhoomika Rajput , C. S. Stalin , Suvendu Rakshit

The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed…

太阳与恒星天体物理 · 物理学 2017-02-08 Jaan Laur , Indrek Kolka , Tõnis Eenmäe , Taavi Tuvikene , Laurits Leedjärv

Long-term (up to 10000d) monitoring has been undertaken for 41 Seyferts in the near-IR (JHKL). All but 2 showed variability, with K ampl in the range <0.1 to > 1.1 mags. The timescale for detectable change is from about one week to a few…

天体物理学 · 物理学 2009-11-10 I. S. Glass

Using three epochs of VLA observations of the Galactic Plane in the first quadrant taken ~15 years apart, we have conducted a search for a population of variable Galactic radio emitters in the flux density range 1-100 mJy at 6 cm. We find…

星系天体物理 · 物理学 2015-05-18 Robert H. Becker , David J. Helfand , Richard L. White , Deanne D. Proctor

To understand the correlation and the radiation mechanism of flare emission in different wavelength bands, we have coordinated a number of telescopes to observe SgrA* simultaneously. We focus only on one aspect of the preliminary results of…

星系天体物理 · 物理学 2010-04-05 F. Yusef-Zadeh , J. Miller-Jones , D. Roberts , M. Wardle , M. Reid , K. Dodds-Eden , D. Porquet , N. Grosso

We present the results of analysing the long-term radio variability of active galactic nuclei at 37 GHz using data of 123 sources observed in the Aalto University Mets\"ahovi Radio Observatory. Our aim was to constrain the characteristic…

星系天体物理 · 物理学 2024-12-12 Sofia Kankkunen , Merja Tornikoski , Talvikki Hovatta , Anne Lähteenmäki

Aims: During the Spectrum Roentgen Gamma (SRG)/ eROSITA all-sky surveys, X-ray sources close to the South Ecliptic Pole (SEP) are observed almost every 4 hours. We aim to identify the sources exhibiting the most significant long-term X-ray…

We report the first systematic analysis of single exposures of all optical and ultraviolet (UV) observations performed by the UltraViolet and Optical Telescope (UVOT) on board the {\em Neil Gehrels Swift Observatory} satellite available up…

高能天体物理现象 · 物理学 2020-09-09 Filippo D'Ammando

We report on the second installment of an X-ray monitoring project of seven luminous radio-quiet quasars (RQQs). New {\sl Chandra} observations of four of these, at $4.10\leq z\leq4.35$, yield a total of six X-ray epochs, per source, with…

高能天体物理现象 · 物理学 2017-10-18 Ohad Shemmer , W. N. Brandt , Maurizio Paolillo , Shai Kaspi , Cristian Vignali , Paulina Lira , Donald P. Schneider

We present the results from a study of the long-term optical spectral variations of BL Lacertae, using the long and well-sampled B and R-band light curves of the Whole Earth Blazar Telescope (WEBT) collaboration, binned on time intervals of…

天体物理学 · 物理学 2019-08-19 I. E. Papadakis , M. Villata , C. M. Raiteri

Context: In 6 years of operation, INTEGRAL/ISGRI revealed more than 500 sources. Many of these sources are variable. Taking into account that nearly half of INTEGRAL/ISGRI sources are new and many of them are still unidentified, the…

高能天体物理现象 · 物理学 2015-05-18 I. Telezhinsky , D. Eckert , V. Savchenko , A. Neronov , N. Produit , T. J. -L. Courvoisier

Aims: During its all-sky survey phase, the eROSITA X-ray telescope onboard SRG scans through the ecliptic poles every 4 hours. This extensive data set of long-duration, frequent, and consistent observations of thousands of X-ray sources is…

天体物理仪器与方法 · 物理学 2024-07-03 David Bogensberger , Kirpal Nandra , Johannes Buchner

We searched a short-term radio variability in an active galactic nucleus PKS 1510-089. A daily flux monitoring for 143 days at 8.4 GHz was performed, and VLBI observations at 8.4, 22, and 43 GHz were carried out 4 times during the flux…

高能天体物理现象 · 物理学 2017-02-22 Akiko Kadota , Kenta Fujisawa , Satoko Sawada-Satoh , Kiyoaki Wajima , Akihiro Doi

We report the flux and spectral variability of PG 1553+113 on intra-night (IDV) to short-term timescales using BVRI data collected over 91 nights from 28 February to 8 November 2019 employing ten optical telescopes: three in Bulgaria, two…

Models of brown dwarf atmospheres suggest they exhibit complex physical behaviour. Observations have shown that they are indeed dynamic, displaying small photometric variations over timescales of hours. Here I report results of infrared…

天体物理学 · 物理学 2009-11-13 C. A. L. Bailer-Jones

We compare the variability properties of very high energy gamma-ray emitting BL Lac objects in the optical and radio bands. We use the variability information to distinguish multiple emission components in the jet, to be used as a guidance…

The All-Sky Automated Survey for Supernovae (ASAS-SN) provides long baseline (${\sim}4$ yrs) $V-$band light curves for sources brighter than V$\lesssim17$ mag across the whole sky. We produced V-band light curves for a total of ${\sim}61.5$…