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Hubble Space Telescope Ultraviolet Spectroscopy of 14 Low-Redshift Quasars
Kaiser, Mary Elizabeth; Laor, Ari; Hall, Patrick B. +35 more
We present low-resolution ultraviolet spectra of 14 low-redshift (zem<~0.8) quasars observed with the Hubble Space Telescope STIS as part of a Snapshot project to understand the relationship between quasar outflows and luminosity. By design, all observations cover the C IV emission line. Ten of the quasars are from the Hamburg-ESO ca…
IGR J17497-2821 : a new X-ray nova
Paltani, S.; Gehrels, N.; Walter, R. +8 more
Context: A new hard X-ray transient has been discovered by INTEGRAL on 2006 Sep. 17 at 1 degree from the Galactic Centre.
Aims: INTEGRAL, Swift/XRT and optical photometric observations are used to characterize
Methods: The X-ray position has been refined to arcsec level through a…
HUDF 1619—A candidate for polar-ring galaxies in the Hubble Ultra Deep Field
Dettmar, R. -J.; Reshetnikov, V. P.
A galaxy that is a good candidate for polar-ring galaxies has been detected in the Hubble Ultra Deep Field (HUDF). The galaxy HUDF 1619 (V ≈ 25 m , z ∼ 1) is the most distant object of this type known to date. A large-scale structure crosses the highly warped disk of the main galaxy seen almost edge-on at an angle of about 70°. The lumi…
Jets or High-Velocity Flows Revealed in High-Cadence Spectrometer and Imager Co-observations?
Doyle, J. G.; Madjarska, M. S.; Curdt, W. +1 more
We report on active region EUV dynamic events observed simultaneously at high cadence with SOHO SUMER and TRACE. Although the features appear in the TRACE Fe IX/X 171 Å images as jets seen in projection on the solar disk, the SUMER spectral line profiles suggest that the plasma has been driven along a curved large-scale magnetic structure, a preex…
Comparison of high- and low-state X-ray spectra in the type 1.5 quasi-stellar object 2MASS 0918+2117
Wilkes, B. J.; Pounds, K. A.
When observed by XMM-Newton in 2003, the type 1.5 quasi-stellar object 2MASS 0918+2117 was found to be in a low state, with an X-ray flux approximately four to five times fainter than during an earlier Chandra observation. The 2-6 keV spectrum was unusually hard (photon index Γ ~ 1.25), with evidence for a reflection-dominated continuum, while a s…
A synchrotron self-Compton model with low-energy electron cut-off for the blazar S5 0716+714
Kirk, J. G.; Tsang, O.
Context: In a self-absorbed synchrotron source with power-law electrons, rapid inverse Compton cooling sets in when the brightness temperature of the source reaches T_B∼1012 K. However, brightness temperatures inferred from observations of intra-day variable sources (IDV) are well above the “Compton catastrophe” limit. This can be under…
Fourier-Resolved Spectroscopy of Active Galactic Nuclei Using XMM-Newton Data. I. The 3-10 keV Band Results
Papadakis, I. E.; Kazanas, D.; Ioannou, Z.
We present the results from Fourier-resolved spectroscopy of archival XMM-Newton data of five AGNs, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051, and Ark 564. This work supplements an earlier study of MCG -6-30-15 and of several Galactic black hole candidate sources. Our results exhibit much larger diversity than for Galactic sources, a fact we a…
An unexpected outburst from A0535+262
Hill, A. B.; Bird, A. J.; Scaringi, S. +6 more
A0535+262 is a transient Be/X-ray binary system which was in a quiescent phase from 1994 to 2005. In this paper we report on the timing and spectral properties of the INTEGRAL detection of the source in 2003 October. The source is detected for ~6000 s in the 18-100 keV energy band at a luminosity of ~3.8 × 1035ergs-1 this is …
Evidence of unrelaxed IGM around IC 1262
Pietsch, W.; Wolter, A.; Breitschwerdt, D. +2 more
Aims:A peculiar morphology of the hot gas was discovered at the center of
Methods: We have exploited the high resolution and sensitivity of Chandra's ACIS-S to invest…
A globular cluster in the dwarf galaxy Sextans B
Sharina, M. E.; Puzia, T. H.; Krylatyh, A. S.
We present spectroscopic observations of a massive globular cluster in the dwarf irregular galaxy Sextans B, discovered by us on the Hubble Space Telescope Wide Field and Planetary Camera 2 (HST WFPC2) images. Long-slit spectra were obtained with the SCORPIO spectrograph on the 6-m telescope at the Special Astrophysical Observatory of the Russian …