X-ray Vision

Ramsey, Brian D.; Elsner, R. F.; Engelhaupt, Darell; Kolodziejczak, J. J.; ODell, S. L.; Speegle, Chet O.; Weisskopf, Martin C.

doi:10.1117/2.5200406.0005

Cited by 4 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Spectra of PHL 1092 were taken on two occasions (2008 January 28 and 2010 October 31) with the Low Resolution Spectrograph (LRS; Hill et al ) on the HET (Ramsey et al ; Shetrone et al ). On each night two 600‐s exposures were obtained with a 1.0‐arcsec slit and the 600 line mm −1 grating.…”

Section: Uv and Optical Spectramentioning

confidence: 99%

Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092

Miniutti

Brandt²,

Schneider³

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

PHL 1092 is a z ∼ 0.4 high‐luminosity counterpart of the class of Narrow‐Line Seyfert 1 galaxies. In 2008, PHL 1092 was found to be in a remarkably low X‐ray flux state during an XMM–Newton observation. Its 2 keV flux density had dropped by a factor of ∼260 with respect to a previous observation performed 4.5 yr earlier. The ultraviolet (UV) flux remained almost constant, resulting in a significant steepening of the optical‐to‐X‐ray slope αox from −1.57 to −2.51, making PHL 1092 one of the most extreme X‐ray weak quasars with no observed broad absorption lines (BALs) in the UV. We have monitored the source since 2008 with three further XMM–Newton observations, producing a simultaneous UV and X‐ray data base spanning almost 10 yr in total in the activity of the source. Our monitoring programme demonstrates that the αox variability in PHL 1092 is entirely driven by long‐term X‐ray flux changes. We apply a series of physically motivated models with the goal of explaining the UV‐to‐X‐ray spectral energy distribution and the extreme X‐ray and αox variability. We consider three possible models. (i) A breathing corona scenario in which the size of the X‐ray‐emitting corona is correlated with the X‐ray flux. In this case, the lowest X‐ray flux states of PHL 1092 are associated with an almost complete collapse of the X‐ray corona down to the marginal stable orbit. (ii) An absorption scenario in which the X‐ray flux variability is entirely due to intervening absorption. If so, PHL 1092 is a quasar with standard X‐ray output for its optical luminosity, appearing as X‐ray weak at times due to absorption. (iii) A disc‐reflection‐dominated scenario in which the X‐ray‐emitting corona is confined within a few gravitational radii from the black hole at all times. In this case, the intrinsic variability of PHL 1092 only needs to be a factor of ∼10 rather than the observed factor of ∼260. We discuss these scenarios in the context of non‐BAL X‐ray weak quasars.

show abstract

Section: Uv and Optical Spectramentioning

confidence: 99%

Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092

Miniutti

Brandt²,

Schneider³

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…In the late 2010 and in the second half of the 2011 the star WTS‐1 was observed during 11 nights with the high‐resolution spectrograph (HRS) housed in the insulated chamber in the basement of the 9.2‐m segmented mirror HET (Ramsey et al ). The HRS is a single‐channel adaptation of the ESO Ultraviolet and Visual Echelle Spectrograph (UVES) spectrometer linked to the corrected prime focus of the HET through its fibre‐fed instrument as described by Tull ().…”

Section: Observationsmentioning

confidence: 99%

The first planet detected in the WTS: an inflated hot Jupiter in a 3.35 d orbit around a late F star

Cappetta

Saglia²,

Birkby³

et al. 2012

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope (UKIRT) in 2007 August. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J ∼ 16 were constructed for ∼60 000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope (HET) allowed us to estimate the spectroscopic parameters of the host star, a late-F main-sequence dwarf (V = 16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 d, a planetary mass of 4.01 ± 0.35 M J and a planetary radius of 1.49 +0.16 −0.18 R J . WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5 M J . The high irradiation from the host star ranks the planet in the pM class.

show abstract

“…This identification scheme differs from other blazar surveys (e.g., the DXRBS survey; Landt et al 2001) and gives a much higher correlation with the 3EG sources. We follow up with optical spectroscopy obtained with the Marcario Low Resolution Spectrograph (LRS; Hill et al 1998) at the HobbyEberly Telescope (HET; Ramsey et al 1998), obtaining source classifications and redshifts.…”

Section: The Discovery Of Q0906ϩ6930mentioning

confidence: 99%

Q0906+6930: The Highest Redshift Blazar

Romani

Sowards-Emmerd

Greenhill

et al. 2004

ApJ

118

View full text Add to dashboard Cite

We report the discovery of a radio-loud flat-spectrum QSO at with properties similar to those of the z p 5.47 EGRET g-ray blazars. This source is the brightest radio QSO at , with a parsec-scale radio jet and a black z 1 5 hole mass estimate տ10 10 M , . It appears to be the most distant blazar discovered to date. High-energy observations of this source can provide powerful probes of the background radiation in the early universe.

show abstract

X-ray Vision

Cited by 4 publications

References 0 publications

Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092

Insights on the X-ray weak quasar phenomenon from XMM-Newton monitoring of PHL 1092

The first planet detected in the WTS: an inflated hot Jupiter in a 3.35 d orbit around a late F star

Q0906+6930: The Highest Redshift Blazar

Contact Info

Product

Resources

About