494 research outputs found
E 0336-248 : A New BL Lac Object Found by an Old Einstein
We obtained new ROSAT HRI and optical observations in the field of the
Einstein X-ray source E 0336-248, which we use to identify it as a 19th
magnitude BL Lacertae object at z=0.251 with an X-ray luminosity of 10^45
erg/s. It is also a 14 mJy radio source at 20 cm. An emission-line galaxy at
z=0.043 that was previously considered a Seyfert identification for E 0336-248
is shown instead to be an unrelated, non-active H II region galaxy that lies 78
arcseconds from the X-ray source. The resolution of this historical case of
mistaken identity illustrates that discoveries of non-AGN emission-line
galaxies with high X-ray luminosity should be tested carefully. The properties
of E 0336-248 are similar to those of other X-ray selected BL Lacs, including
its location in an apparent group or cluster of galaxies. Somewhat unusual is
the weak contribution of nonstellar optical light relative to the starlight in
the spectrum of its host galaxy, which raises once again the possibility that
even high-luminosity BL Lac objects may be difficult to identify in X-ray
selected samples. We discuss a possible manifestation of this problem that
appeared in the recent literature.Comment: To appear in the Astronomical Journal. 8 pages including figures
(uses psfig.tex, also included
Chandra detection of a parsec scale wind in the Broad Line Radio Galaxy 3C 382
We present unambiguous evidence for a parsec scale wind in the Broad-Line
Radio Galaxy (BLRG) 3C 382, the first radio-loud AGN, with , whereby an outflow has been measured with
X-ray grating spectroscopy. A 118 ks Chandra grating (HETG) observation of 3C
382 has revealed the presence of several high ionization absorption lines in
the soft X-ray band, from Fe, Ne, Mg and Si. The absorption lines are
blue-shifted with respect to the systemic velocity of 3C 382 by -840\pm60 km/s
and are resolved by Chandra with a velocity width of 340\pm70 km/s. The outflow
appears to originate from a single zone of gas of column density cm and ionization parameter . From
the above measurements we calculate that the outflow is observed on parsec
scales, within the likely range from 10-1000 pc, i.e., consistent with an
origin in the Narrow Line Region.Comment: 11 pages, accepted for publication in Astrophysical Journal Letter
A deep look at the inner regions of the mini-BAL QSO PG 1126-041 with XMM-Newton
A long XMM-Newton observation of the mini-BAL QSO PG 1126-041 allowed us to
detect a highly ionized phase of X-ray absorbing gas outflowing at v~15000
km/s. Physical implications are briefly discussed.Comment: 2 pages, 2 figures. Proceedings of "X.ray Astronomy 2009", Bologna
09/7-11/2009, AIP Conference Series, Eds. A. Comastri, M. Cappi, L. Angelin
The Wide-Angle Outflow of the Lensed z = 1.51 AGN HS 0810+2554
We present results from X-ray observations of the gravitationally lensed z =
1.51 AGN HS 0810+2554 performed with the Chandra X-ray Observatory and
XMM-Newton. Blueshifted absorption lines are detected in both observations at
rest-frame energies ranging between ~1-12 keV at > 99% confidence. The inferred
velocities of the outflowing components range between ~0.1c and ~0.4c. A strong
emission line at ~6.8 keV accompanied by a significant absorption line at ~7.8
keV is also detected in the Chandra observation. The presence of these lines is
a characteristic feature of a P-Cygni profile supporting the presence of an
expanding outflowing highly ionized iron absorber in this quasar. Modeling of
the P-Cygni profile constrains the covering factor of the wind to be > 0.6,
assuming disk shielding. A disk-reflection component is detected in the
XMM-Newton observation accompanied by blueshifted absorption lines. The
XMM-Newton observation constrains the inclination angle to be < 45 degrees at
90% confidence, assuming the hard excess is due to blurred reflection from the
accretion disk. The detection of an ultrafast and wide-angle wind in an AGN
with intrinsic narrow absorption lines (NALs) would suggest that quasar winds
may couple efficiently with the intergalactic medium and provide significant
feedback if ubiquitous in all NAL and BAL quasars. We estimate the mass-outflow
rate of the absorbers to lie in the range of 1.5 and 3.4 Msolar/yr for the two
observations. We find the fraction of kinetic to electromagnetic luminosity
released by HS 0810+2554 is large (epsilon = 9 (-6,+8)) suggesting that
magnetic driving is likely a significant contributor to the acceleration of
this outflow.Comment: 27 pages, 13 figures, Accepted for publication in Ap
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