Browsing University of Galway Support Services by Subject "lac objects"
Now showing items 1-16 of 16
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A multiwavelength view of the tev blazar markarian 421: correlated variability, flaring, and spectral evolution
(IOP Publishing, 2005-09-01)We report results from an intensive multiwavelength monitoring campaign on the TeV blazar Mrk 421 over the period of 2003 - 2004. The source was observed simultaneously at TeV energies with the Whipple 10 m telescope and ... -
A search for spectral hysteresis and energy-dependent time lags from x-ray and tev gamma-ray observations of mrk 421
(American Astronomical Society, 2016-12-22)Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the ... -
A search for tev gamma‐ray emission from high‐peaked flat‐spectrum radio quasars using the whipple air cerenkov telescope
(IOP Publishing, 2004-10-01)Blazars have traditionally been separated into two broad categories based on their optical emission characteristics. Blazars with faint or no emission lines are referred to as BL Lacertae objects ( BL Lacs), and blazars ... -
Constraints on the very high energy emission from bl lacertae objects
(IOP Publishing, 2004-03-01)We present results from observations of 29 BL Lacertae objects, taken with the Whipple Observatory 10 m gamma-ray telescope between 1995 and 2000. The observed objects are mostly at low redshift (z<0.2), but observations ... -
Discovery of high-energy and very high energy γ-ray emission from the blazar rbs 0413
(IOP Publishing, 2012-04-18)We report on the discovery of high-energy (HE; E &gt; 0.1 GeV) and very high energy (VHE; E &gt; 100 GeV) gamma-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based gamma-ray ... -
Long term observations of b2 1215+30 with veritas
(IOP Publishing, 2013-11-27)We report on VERITAS observations of the BL Lac object B2 1215+30 between 2008 and 2012. During this period, the source was detected at very high energies (VHEs; E &gt; 100 GeV) by VERITAS with a significance of 8.9s ... -
Multiwavelength observations and modeling of 1es 1959+650 in a low flux state
(IOP Publishing, 2013-08-27)We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007-2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (sigma) significance in ... -
Multiwavelength observations of a tev-flare from w comae
(IOP Publishing, 2009-11-24)We report results from an intensive multiwavelength campaign on the intermediate-frequency-peaked BL Lacertae object W Com (z = 0.102) during a strong outburst of very high energy gamma-ray emission in 2008 June. The very ... -
Multiwavelength observations of markarian 421 in 2005-2006
(IOP Publishing, 2009-03-31)Since 2005 September, the Whipple 10 m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five northern hemisphere blazars that have already been detected at the Whipple Observatory, Markarian 421 ... -
Multiwavelength observations of the blazar bl lacertae: a new fast tev gamma-ray flare
(American Astronomical Society, 2018-03-28)Combined with measurements made by very-long-baseline interferometry, the observations of fast TeV gamma-ray flares probe the structure and emission mechanism of blazar jets. However, only a handful of such flares have ... -
Multiwavelength observations of the blazar markarian 421 in 2002 december and 2003 january
(IOP Publishing, 2006-04-20)We report on a multiwavelength campaign on the TeV gamma-ray blazar Mrk 421 performed during 2002 December and 2003 January. These target of opportunity observations were initiated by the detection of X-ray and TeV gamma-ray ... -
Multiwavelength study of quiescent states of mrk 421 with unprecedented hard x-ray coverage provided bynustarin 2013
(American Astronomical Society, 2016-03-09)We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and ... -
Observation of gamma‐ray emission from the galaxy m87 above 250 gev with veritas1
(IOP Publishing, 2008-05-20)The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring in active galactic nuclei from radio waves to TeV gamma-rays. Here we report the detection ... -
The discovery of γ-ray emission from the blazar rgb j0710+591
(IOP Publishing, 2010-04-30)The high-frequency-peaked BL Lacertae object RGB J0710+591 was observed in the very high-energy (VHE; E &gt; 100 GeV) wave band by the VERITAS array of atmospheric Cherenkov telescopes. The observations, taken between ... -
The june 2008 flare of markarian 421 from optical to tev energies
(IOP Publishing, 2008-12-30)We present optical, X-ray, high-energy ((sic) 30 GeV) and very high energy ((sic) 100 GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken between 2008 May 24 and June 23. A high-energy gamma-ray signal ... -
Veritas and multiwavelength observations of the bl lacertae object 1es 1741+196
(Oxford University Press (OUP), 2016-04-01)We present results from multiwavelength observations of the BL Lacertae object 1ES 1741 + 196, including results in the very high energy gamma-ray regime using the Very Energetic Radiation Imaging Telescope Array System ...