Search Publications
Mid-Infrared Spectral Diagnostics of Nuclear and Extranuclear Regions in Nearby Galaxies
Helou, G.; Moustakas, J.; Roussel, H. +19 more
Mid-infrared diagnostics are presented for a large portion of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample plus archival data from ISO and Spitzer. The SINGS data set includes low- and high-resolution spectral maps and broadband imaging in the infrared for over 160 nuclear and extranuclear regions within 75 nearby galaxies spanning a…
A Recalibration of Optical Photometry: Tycho-2, Strömgren, and Johnson Systems
Maíz Apellániz, J.
I use high-quality Hubble Space Telescope (HST) spectrophotometry to analyze the calibration of three popular optical photometry systems: Tycho-2 BT and VT, Strömgren uvby, and Johnson UBV. For Tycho-2, I revisit the analysis of an earlier paper to include the new recalibration of grating/aperture corrections, vignetting, and charge transfer ineff…
The Outburst of HST-1 in the M87 Jet
Cheung, C. C.; Sparks, W. B.; Wilson, A. S. +4 more
The X-ray intensity of knot HST-1, 0.85" from the nucleus of the radio galaxy M87, has increased by more than a factor of 50 during the last 5 yr. The optical increase is similar, and our more limited radio data indicate a commensurate activity. We give the primary results of our Chandra X-Ray Observatory monitoring program and consider some of th…
The Second IBIS/ISGRI Soft Gamma-Ray Survey Catalog
Hill, A. B.; Mas-Hesse, J. M.; Walter, R. +21 more
In this paper we report the second soft gamma-ray source catalog obtained with the IBIS/ISGRI gamma-ray imager on board the INTEGRAL satellite. The scientific data set is based on more than 10 Ms of high-quality observations performed during the first 2 years of Core Program and public IBIS/ISGRI observations, and covers ~50% of the whole sky. The…
The luminosity function of young star clusters: implications for the maximum mass and luminosity of clusters
Bastian, N.; Larsen, S. S.; Gieles, M. +1 more
We introduce a method to relate a possible truncation of the star cluster mass function at the high mass end to the shape of the cluster luminosity function (LF). We compare the observed LFs of five galaxies containing young star clusters with synthetic cluster population models with varying initial conditions. The LF of the SMC, the LMC and NGC 5…
Scaling Mass Profiles around Elliptical Galaxies Observed with Chandra and XMM-Newton
Fukazawa, Y.; Botoya-Nonesa, J. G.; Pu, J. +2 more
We investigated the dynamical structure of 53 elliptical galaxies using the Chandra archival X-ray data. In X-ray-luminous galaxies, temperature increases with radius and gas density is systematically higher at the optical outskirts, indicating the presence of a significant amount of the group-scale hot gas. In contrast, X-ray-dim galaxies show a …
Kinetic simulations of ring current evolution during the Geospace Environment Modeling challenge events
Thomsen, M. F.; Mouikis, C. G.; Jordanova, V. K. +5 more
We investigate the temporal and spatial evolution of the ring current during two storms selected for study by the Geospace Environment Modeling (GEM) program using our kinetic drift-loss model coupled with a time-dependent plasmasphere model. We use geosynchronous data from LANL satellites to model the inflow of plasma from the magnetotail. We com…
X-ray sources and magnetic reconnection in the X3.9 flare of 2003 November 3
Magdalenić, J.; Temmer, M.; Veronig, A. M. +5 more
Context: .Recent RHESSI observations indicate an apparent altitude decrease of flare X-ray loop-top (LT) sources before changing to the commonly observed upward growth of the flare loop system.
Aims: .We performed a detailed study of the LT altitude decrease for one well observed flare in order to find further hints on the physics of this phen…
Identification of the Red Supergiant Progenitor of Supernova 2005cs: Do the Progenitors of Type II-P Supernovae Have Low Mass?
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Livio, Mario +5 more
The stars that end their lives as supernovae (SNe) have been directly observed in only a handful of cases, mainly because of the extreme difficulty of identifying them in images obtained prior to the SN explosions. Here we report the identification of the progenitor for the recent Type II-plateau (core collapse) SN 2005cs in pre-explosion archival…
XMM-Newton study of the complex and variable spectrum of NGC 4051
Maraschi, L.; Cappi, M.; Ponti, G. +3 more
We study the X-ray spectral variability of the narrow line Seyfert 1 galaxy NGC 4051 as observed during two XMM-Newton observations. To gain insight on the general behaviour, we first apply model-independent techniques such as rms spectra and flux-flux plots. We then perform time-resolved spectral analysis by splitting the observations into 68 spe…