Search Publications
The Lyα Forest of a Lyman Break Galaxy: Very Large Telescope Spectra of MS 1512-cB58 at z=2.724
Panagia, N.; Padovani, P.; Savaglio, S.
The high-redshift galaxy MS 1512-cB58 (z=2.724, mV=20.64) has been observed with the very efficient high-resolution UV-Visual Eschelle Spectograph on the Very Large Telescope. Although this is a very challenging observational program for a Southern Hemisphere telescope (the galaxy is located at +36° declination), high-resolution spectra…
NICMOS Snapshot Survey of Damped Lyα Quasars
Malkan, Matthew A.; Colbert, James W.
We image 19 quasars with 22 damped Lyα systems (DLAs) using the F160W filter and the Near-Infrared Camera and Multi-Object Spectrograph on board the Hubble Space Telescope in both direct and coronagraphic modes. We reach 5 σ detection limits of ~H=22 in the majority of our images. We compare our observations to the observed Lyman break population …
Infrared Space Observatory Investigates the Nature of Extremely Red Hard X-Ray Sources Responsible for the X-Ray Background
Elbaz, D.; Franceschini, A.; Flores, H. +3 more
We analyze very deep X-ray and mid-IR surveys in common areas of the Lockman Hole and the Hubble Deep Field-North (HDF-N) to study the sources of the X-ray background (XRB) and to test the standard obscured accretion paradigm. Observations with XMM-Newton and Infrared Space Observatory (ISO) of a substantial area in Lockman are particularly import…
Multiwavelength Observations of the Peculiar Planetary Nebula IC 2149
López, J. A.; Torrelles, J. M.; Miranda, L. F. +4 more
We report high- and low-dispersion spectroscopy, optical imaging, and high-resolution Very Large Array-A λ3.6 cm continuum observations of the peculiar planetary nebula IC 2149. These observations show that ``bipolar'' is a suitable morphological classification for IC 2149. Most nebular material is concentrated in a knotty, bright ring seen edge-o…
Metric Radio Observations and Ray-tracing Analysis of the Onset Phase of a Solar Eruptive Event
Ramesh, R.; Kathiravan, C.; Subramanian, K. R.
We report metric radio observations and the results obtained using two-dimensional ray-tracing analysis of the solar corona close to the onset phase of the exceptionally bright prominence eruption and the associated massive coronal mass ejection (CME) of 1998 June 2. The average electron density of the observed radio enhancements at the location o…
Hiding in Plain Sight: Chandra Observations of the Quiescent Neutron Star 4U 2129+47 in Eclipse
Nowak, Michael A.; Heinz, Sebastian; Begelman, M. C.
During a previous outburst phase, the neutron star 4U 2129+47 exhibited evidence for a spatially extended accretion disk corona via broad, partial X-ray eclipses occurring periodically on the 5.24 hr orbit. Since 1983, however, 4U 2129+47 has entered a quiescent state several orders of magnitude fainter. We have performed a 37 ks (~two binary orbi…
Hubble Space Telescope NICMOS Observations of the Polarization of NGC 1068
Hines, Dean C.; Schultz, A. S. B.; Trammell, Susan R. +3 more
We have observed the polarized light at 2 µm in the center of NGC 1068 with NICMOS Camera 2 on the Hubble Space Telescope. The nucleus is dominated by a bright, unresolved source, polarized at a level of 6.0%+/-1.2% with a position angle of 122deg+/-15deg. There are two polarized lobes extending up to 8" northeast and s…
Hubble Space Telescope Proper Motion Confirms the Optical Identification of the Nearby Pulsar PSR 1929+10
De Luca, Andrea; Caraveo, Patrizia A.; Becker, Werner +1 more
We report on the proper-motion measurement of the proposed optical counterpart of the X-ray/radio pulsar PSR 1929+10. Using images obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS; average epoch 2001.73), we computed a yearly displacement of +97+/-1 mas yr-1 in right ascension and +46+/-1 mas yr<…
Young Stellar Nuclei in Lenticular Galaxies: NGC 5574 and NGC 7457
Chavushyan, V. H.; Sil'chenko, O. K.; Afanasiev, V. L. +1 more
The stellar population properties in the centers of NGC 5574 and NGC 7457 (two lenticular galaxies previously shown to have radially homogeneous blue optical-band colors) are studied by means of integral-field spectroscopy. The compact nuclei of the galaxies appear to be chemically distinct: in NGC 5574 the nucleus is distinguished by a higher tha…
The Differential Emission Measure Distribution in the Multiloop Corona
Aschwanden, Markus J.
This is a rebuttal of a recent Letter on the inadequacy of temperature measurements in the solar corona through narrowband filter and line ratios by Martens et al. We simulate the differential emission measure (DEM) distribution of a multiloop corona and find that the temperature profile of individual loops can be retrieved with narrowband filter …