Search Publications
The host galaxy/AGN connection in nearby early-type galaxies. A new view of the origin of the radio-quiet/radio-loud dichotomy?
Capetti, A.; Balmaverde, B.
This is the third in a series of three papers exploring the connection between the multiwavelength properties of AGN in nearby early-type galaxies and the characteristics of their hosts. Starting from an initial sample of 332 galaxies, we selected 116 AGN candidates requiring the detection of a radio source with a flux limit of ~1 mJy, as measured…
The UV spectrum of HS 1700+6416. II. FUSE observations of the He II Lyman alpha forest
Shull, J. M.; Zheng, W.; Moos, H. W. +11 more
Aims.We present the far-UV spectrum of the quasar
Chandra ACIS Spectroscopy of N157B: A Young Composite Supernova Remnant in a Superbubble
Gotthelf, E. V.; Chu, You-Hua; Wang, Q. Daniel +3 more
We present a Chandra ACIS observations of N157B, a young supernova remnant (SNR) located in the 30 Doradus star formation region of the Large Magellanic Cloud. This remnant contains the most energetic pulsar known (PSR J053747.39-691020.2 E˙=4.8×1038 ergs s-1), which is surrounded by a X-ray-bright nonthermal nebula that like…
INTEGRAL observation of the high-mass X-ray transient V 0332+53 during the 2005 outburst decline
Rodriguez, J.; Mowlavi, N.; Wilms, J. +7 more
The decline of the high mass X-ray transient V 0332+53 during the Dec. 2004 to Feb. 2005 outburst is analysed from the data recorded by INTEGRAL. The flux is shown to decrease exponentially until 2005 Feb. 10, with a decay time scale of ~30 days above 20 keV and ~20 days at lower energies, and to decrease linearly thereafter. The energy spectrum i…
The Circumstellar Environments of NML Cygni and the Cool Hypergiants
Humphreys, Roberta M.; Marengo, Massimo; Schuster, Michael T.
We present high-resolution HST WFPC2 images of compact nebulosity surrounding the cool M-type hypergiants NML Cyg, VX Sgr, and S Per. The powerful OH/IR source NML Cyg exhibits a peculiar bean-shaped asymmetric nebula that is coincident with the distribution of its H2O vapor masers. We show that NML Cyg's circumstellar envelope is likel…
Long-lived geomagnetic storms and coronal mass ejections
Gopalswamy, N.; Yashiro, S.; Lara, A. +3 more
Coronal mass ejections (CMEs) are major solar events that are known to cause large geomagnetic storms (Dst < -100 nT). Isolated geomagnetic storms typically have a main phase of 3-12 hours and a recovery phase of around 1 day. However, there are some storms with main and recovery phases exceeding ∼3 days. We trace the origin of these long-lived…
The Fundamental Plane for z = 0.8-0.9 Cluster Galaxies
Jørgensen, Inger; Chiboucas, Kristin; Barr, Jordi +3 more
We present the fundamental plane (FP) for 38 early-type galaxies in the two rich galaxy clusters RX J0152.7-1357 (z=0.83) and RX J1226.9+3332 (z=0.89), reaching a limiting magnitude of MB=-19.8 in the rest frame of the clusters. While the zero-point offset of the FP for these high-redshift clusters relative to our low-redshift sample is…
The Low-z Intergalactic Medium. II. Lyβ, O VI, and C III Forest
Shull, J. Michael; Danforth, Charles W.; Stocke, John T. +1 more
We present the results of a large survey of H I, O VI, and C III absorption lines in the low-redshift (z<0.3) intergalactic medium (IGM). We begin with 171 strong Lyα absorption lines (Wλ>=80 mÅ) in 31 AGN sight lines studied with the Hubble Space Telescope and measure corresponding absorption from higher order Lyman lines with FU…
Measuring M Dwarf Winds with DAZ White Dwarfs
Debes, John H.
Hydrogen atmosphere white dwarfs with metal lines, so-called DAZs, show evidence for ongoing accretion of material onto their surfaces. Some DAZs are known to have unresolved M dwarf companions, which could account for the observed accretion through a stellar wind. I combine observed Ca abundances of the DAZs with information on the orbital separa…
Probing the Faintest Stars in a Globular Star Cluster
Anderson, Jay; Rich, R. Michael; Stetson, Peter B. +10 more
NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed an ultradeep color-magnitude diagram for this cluster. We see a clear truncation in each of its two major stellar sequences. Faint red main-sequence stars run out well above our observational limit and near to th…