The Swift Ultra-Violet/Optical Telescope

Roming, P. W. A.; Kennedy, Thomas E.; Mason, K. O.; Nousek, J. A.; Ahr, Lindy; Bingham, R. G.; Broos, P. S.; Carter, Mary J.; Hancock, B.; Huckle, H.; Hunsberger, S.; Kawakami, Hiroyoshi; Killough, Ronnie; Koch, T. S.; McLelland, M.; Smith, K. D.; Smith, Philip J.; Soto, Juan Carlos; Boyd, Patricia T.; Breeveld, A. A.; Holland, S. T.; Ivanushkina, M.; Pryzby, Michael S.; Still, M.; Stock, J.

doi:10.1007/s11214-005-5095-4

Cited by 1,903 publications

(1,508 citation statements)

References 30 publications

Supporting

Mentioning

1,501

Contrasting

Order By: Relevance

“…We observed J1118 on 2013 June 27 with the Ultraviolet/Optical Telescope (UVOT; Roming et al 2005) onboard SWIFT (Gehrels et al 2004), using the uvw1 (1554 s), uvm2 (1428 s), and uvw2 (1554 s) filters (PI Homan). Individual frames were combined using the tool uvotimsum.…”

Section: Ultravioletmentioning

confidence: 99%

Constraints on relativistic jets in quiescent black hole X-ray binaries from broad-band spectral modelling

Plotkin

Gallo

Markoff

et al. 2014

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The nature of black hole jets at the lowest detectable luminosities remains an open question, largely due to a dearth of observational constraints. Here, we present a new, nearly-simultaneous broadband spectrum of the black hole X-ray binary (BHXB) XTE J1118+480 at an extremely low Eddington ratio (L X ∼ 10 −8.5 L Edd ). Our new spectral energy distribution (SED) includes the radio, near-infrared, optical, ultraviolet, and X-ray wavebands. XTE J1118+480 is now the second BHXB at such a low Eddington ratio with a well-sampled SED, thereby providing new constraints on highly sub-Eddington accretion flows and jets, and opening the door to begin comparison studies between systems. We apply a multi-zone jet model to the new broadband SED, and we compare our results to previous fits to the same source using the same model at 4-5 decades higher luminosity. We find that after a BHXB transitions to the so-called quiescent spectral state, the jet base becomes more compact (by up to an order of magnitude) and slightly cooler (by at least a factor of two). Our preferred model fit indicates that jet particle acceleration is much weaker after the transition into quiescence. That is, accelerated non-thermal particles no longer reach high enough Lorentz factors to contribute significant amounts of synchrotron X-ray emission. Instead, the X-ray waveband is dominated by synchrotron self-Compton emission from a population of mildly relativistic electrons with a quasi-thermal velocity distribution that are associated with the jet base. The corresponding (thermal) synchrotron component from the jet base emits primarily in the infrared through ultraviolet wavebands. Our results on XTE J1118+480 are consistent with broadband modeling for A0620-00 (the only other comparably low Eddington ratio BHXB with a well-sampled SED) and for Sgr A* (the quiescent supermassive black hole at the Galactic center). The above could therefore represent a canonical baseline geometry for accreting black holes in quiescence. We conclude with suggestions for future studies to further investigate the above scenario.

show abstract

Section: Ultravioletmentioning

confidence: 99%

Constraints on relativistic jets in quiescent black hole X-ray binaries from broad-band spectral modelling

Plotkin

Gallo

Markoff

et al. 2014

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…These authors also measured an absorbed flux in the 0.3-10 keV band of 5.6 × 10 −12 erg cm −2 s −1 and predicted a flux in the 14-195 keV band of 4.0 × 10 −11 erg cm −2 s −1 , comparable with the BAT detection of Okajima et al (2006). Tueller et al (2006) detected no sources with Swift/UVOT (Roming et al 2005) in the XRT error circle at a limiting magnitude of 20 in the ultraviolet filters. The soft X-ray position of Swift J1656.3−3302 is consistent with the radio source NVSS J165616−330211 (having a 1.4 GHz flux density of 410.7 ± 12.3 mJy; Condon et al 1998) and (albeit marginally) with the faint ROSAT source 1RXS J165616.6−330150 (Voges et al 2000).…”

Section: Previous Information On Swift J16563-3302mentioning

confidence: 99%

High-redshift blazar identification for Swift J1656.3-3302

Masetti

Mason

Landi

et al. 2008

A&A

View full text Add to dashboard Cite

We report on the high-redshift blazar identification of a new gamma-ray source, Swift J1656.3−3302, detected with the BAT imager onboard the Swift satellite and the IBIS instrument on the INTEGRAL satellite. Follow-up optical spectroscopy has allowed us to identify the counterpart as an R ∼ 19 mag source that shows broad Lyman-α, Si iv, He ii, C iv, and C iii] emission lines at redshift z = 2.40 ± 0.01. Spectral evolution is observed in X-rays when the INTEGRAL/IBIS data are compared to the Swift/BAT results, with the spectrum steepening when the source gets fainter. The 0.7-200 keV X-ray continuum, observed with Swift/XRT and INTEGRAL/IBIS, shows the power law shape typical of radio loud (broad emission line) active galactic nuclei (with a photon index Γ ∼ 1.6) and a hint of spectral curvature below ∼2 keV, possibly due to intrinsic absorption (N H ∼ 7× 10 22 cm −2 ) local to the source. Alternatively, a slope change (∆Γ ∼ 1) around 2.7 keV can describe the X-ray spectrum equally well. At this redshift, the observed 20-100 keV luminosity of the source is ∼10 48 erg s −1 (assuming isotropic emission), making Swift J1656.3−3302 one of the most X-ray luminous blazars. This source is yet another example of a distant gamma-ray loud quasar discovered above 20 keV. It is also the farthest object, among the previously unidentified INTEGRAL sources, whose nature has been determined a posteriori through optical spectroscopy.

show abstract

“…Grade filtering was applied by selecting the 0-2 and 0-12 ranges for the WT mode and PC mode data, respectively. Using 699 s of overlapping XRT Photon Counting mode and UVOT (UV-Optical Telescope, Roming et al 2005) V-band data, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching to the USNO-B1 catalogue, see Goad et al 2007) which is RA = 22 h 08 m 32.23 s , Dec = -74 d 34 49.1 (J2000.0) with an uncertainty of 1.7 (radius, 90% containment). This is 1.5 from the XRT position .…”

Section: Xrtmentioning

confidence: 99%

A study of the prompt and afterglow emission of the short GRB 061201

Stratta¹,

D’Avanzo

Piranomonte

et al. 2007

A&A

View full text Add to dashboard Cite

Context. Our knowledge of the intrinsic properties of short duration Gamma-Ray Bursts has relied, so far, only upon a few cases for which the estimate of the distance and an extended, multiwavelength monitoring of the afterglow have been obtained. Aims. We carried out multiwavelength observations of the short GRB 061201 aimed at estimating its distance and studying its properties. Methods. We performed a spectral and timing analysis of the prompt and afterglow emission and discuss the results in the context of the standard fireball model. Results. A clear temporal break was observed in the X-ray light curve about 40 min after the burst trigger. We find that the spectral and timing behaviour of the X-ray afterglow is consistent with a jet origin of the observed break, although the optical data can not definitively confirm this and other scenarios are possible. No underlying host galaxy down to R ∼ 26 mag was found after fading of the optical afterglow. Thus, no secure redshift could be measured for this burst. The nearest galaxy is at z = 0.111 and shows evidence of star formation activity. We discuss the association of GRB 061201 with this galaxy and with the ACO S 995 galaxy cluster, from which the source is at an angular distance of 17 and 8.5 , respectively. We also test the association with a possible undetected, positionally consistent galaxy at z ∼ 1. In all these cases, in the jet interpretation, we find a jet opening angle of 1-2 degrees.Key words. gamma rays: bursts IntroductionShort duration Gamma-ray Bursts (GRBs) are historically defined as those GRBs with burst duration less than two seconds and hard spectra (Kouveliotou et al. 1993). As the sample of short GRBs increases, in order to take into account all the spectral and temporal properties of the prompt emission, alternative empirical definitions of short GRBs have been introduced (e.g. Norris & Bonnell 2006;Zhang et al. 2007).The expected progenitor for short GRBs is a merging binary system of compact objects. However, our present knowledge of the intrinsic properties of short bursts mainly relies upon a few cases for which the distance could be derived and an extendedThe results reported in this paper are partially based on observations carried out at ESO telescopes under program 078.D-0809.INAF personnel resident at ASDC. multiwavelength monitoring of the afterglow was carried out.From these it appears that short bursts are less energetic and less collimated than long GRBs (e.g. Fox et al. 2005;Burrows et al. 2006;Soderberg et al. 2006). Intrinsic spectral parameters such as the peak energy E p of the EF(E) spectrum of the burst and the equivalent isotropic energy E iso , do not match the E p − E iso correlation for long GRBs (e.g. Amati 2007).The short bursts for which unambiguous hosts have been found are at redshifts between z = 0.10 and z = 0.55. The optical afterglows of seven short bursts and their likely host galaxies have been recently observed with telescopes such as ESO/VLT, Gemini, Magellan and HST, but no firm estimation of...

show abstract

The Swift Ultra-Violet/Optical Telescope

Cited by 1,903 publications

References 30 publications

Constraints on relativistic jets in quiescent black hole X-ray binaries from broad-band spectral modelling

Constraints on relativistic jets in quiescent black hole X-ray binaries from broad-band spectral modelling

High-redshift blazar identification for Swift J1656.3-3302

A study of the prompt and afterglow emission of the short GRB 061201

Contact Info

Product

Resources

About