相关论文: The Intrinsically X-ray Weak Quasar PHL 1811. II. …
We present NuSTAR hard X-ray (3-79 keV) observations of three Type 2 quasars at z ~ 0.4-0.5, optically selected from the Sloan Digital Sky Survey (SDSS). Although the quasars show evidence for being heavily obscured Compton-thick systems on…
Broad emission-line outflows of active galactic nuclei (AGNs) have been proposed for many years but are very difficult to quantitatively study because of the coexistence of the gravitationally-bound and outflow emission. We present detailed…
UVES spectra of the very young (~10^7 years) peculiar B-type star HR 6000 were analyzed in the near-UV and visual spectral regions (3050-9460 A) with the aim to extend to other spectral ranges the study made previously in the UV using IUE…
We present a high spectral resolution optical spectrum of the bright quasar Q~1037-2704. The large number of absorption systems suggests the presence of an intervening supercluster, but the issue remains controversial.\par We demonstrate…
Quasar outflows are fundamental components of quasar environments that might play an important role in feedback to galaxy evolution. We report on the emergence of a remarkable new outflow absorption-line system in the quasar PG1411+442…
The persistent, low-luminosity neutron star X-ray binary 4U 1812-12 is a potential member of the scarce family of ultra-compact systems. We performed deep photometric and spectroscopic optical observations with the 10.4 m Gran Telescopio…
Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong FeII emission, large and fast X-ray variability, rather steep 2-10 keV spectrum. These intriguing objects have been suggested to be the…
We present low-resolution ultraviolet spectra of 14 low redshift (z<0.8) quasars observed with HST/STIS as part of a Snap project to understand the relationship between quasar outflows and luminosity. By design, all observations cover the…
We characterize the Ly$\alpha$ halo and absorption systems toward PSO J083+11, a unique $z=6.3401$ weak-line quasar, using Gemini/GNIRS, Magellan/FIRE, and VLT/MUSE data. Strong absorptions by hydrogen and several metal lines (e.g., CII,…
IRAS F11119+3257 is a quasar-dominated Ultra-Luminous InfraRed Galaxy, with a partially obscured narrow-line seyfert 1 nucleus. In this paper, we present the NIR spectroscopy of F11119+3257, in which we find unusual Paschen emission lines,…
We report on imaging and spectroscopic observations of the radio-loud, highly polarized quasar PKS 1610-771 (z = 1.71). Our long-slit spectroscopy of the companion 4.55 arcseconds NW of the quasar confirms the stellar nature of this object,…
In this paper we present a broad-band study of the X-ray emission of the blazar PKS1830-211 based on Chandra and Integral observations. Notwithstanding the high redshift (z=2.507), it is a bright X-ray source (F(2-10 keV)~10^{-11} erg…
We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7 <= z <= 2.7 in order to characterize the relative UV and X-ray spectral properties of QSOs that…
We have analyzed GHRS data of eight CTTS and one WTTS. The GHRS data consists of spectral ranges 40 A wide centered on 1345, 1400, 1497, 1550, and 1900 A. These UV spectra show strong SiIV, and CIV emission, and large quantities of sharp…
We present infrared spectroscopy from the Spitzer Space Telescope at one disk position and two positions at a height of 1 kpc from the disk in the edge-on spiral NGC 891, with the primary goal of studying halo ionization. Our main result is…
We present results on the X-ray spectra of the radio-loud, high-polarization quasar, PKS 1510-089, based on new data obtained using ASCA, and from archival ROSAT data. The X-ray spectrum obtained by ASCA is unusually hard, with the photon…
The neutral hydrogen and the ionized helium absorption in the spectra of quasars are unique probes of structure in the early universe. We present Far-Ultraviolet Spectroscopic Explorer observations of the line of sight to the quasar…
We report the discovery of the faint (V=21.7) quasar QSO03027-0010 at z=2.808 in the vicinity of Q0302-003, one of the few quasars observed with STIS to study intergalactic HeII absorption. Together with another newly discovered QSO at…
We report the first mid-IR detection of highly disturbed ionized gas in the ultraluminous infrared galaxy IRAS F00183-7111. The gas, traced by the 12.81um [NeII] and 15.56um [NeIII] lines, spans a velocity range of-3500 to 3000 km/s with…
We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z=0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z<1.3. However, their rest-frame 2…