Search Publications
On the Radial Extent of the Dwarf Irregular Galaxy IC10
Walker, A. R.; Prada Moroni, P. G.; Degl'Innocenti, S. +15 more
We present new deep and accurate space (Advanced Camera for Surveys-Wide Field Planetary Camera 2 on board the Hubble Space Telescope) and ground-based (Suprime-Cam at Subaru Telescope, Mega-Cam at Canada-France-Hawaii Telescope) photometric and astrometric data for the Local Group dwarf irregular IC10. We confirm the significant decrease of the y…
Spitzer mid-infrared observations of seven bipolar planetary nebulae
Ramos-Larios, G.; Phillips, J. P.
We have investigated the mid-infrared (MIR) and visual structures of seven bipolar planetary nebulae (BPNe), using imaging and spectroscopy acquired using the Spitzer Space Telescope (SST), and the Observatorio Astronomico Nacional in Mexico. The results show that the sources are more extended towards longer MIR wavelengths, as well as having high…
Spatially resolved XMM-Newton analysis and a model of the nonthermal emission of MSH 15-52
de Jager, O. C.; Büsching, I.; Eger, P. +2 more
We present an X-ray analysis and a model of the nonthermal emission of the pulsar wind nebula (PWN) MSH 15-52. We analyzed XMM-Newton data to obtain the spatially resolved spectral parameters around the pulsar PSR B1509-58. A steepening of the fitted power-law spectra and decrease in the surface brightness is observed with increasing distance from…
Swift Observations of the Ultraluminous X-ray Source Holmberg IX X-1
Kaaret, P.; Kong, A. K. H.; Feng, H. +2 more
Holmberg IX X-1 is a well-known ultraluminous X-ray source with an X-ray luminosity of ~1040 erg s-1. The source has been monitored by the X-ray telescope of Swift regularly. Since 2009 April, the source has been in an extended low luminosity state. We utilize the co-added spectra taken at different luminosity states to study…
Interstellar extinction and the distribution of stellar populations in the direction of the ultra-deep Chandra Galactic field
Revnivtsev, M.; van den Berg, M.; Grindlay, J. E. +3 more
We studied the stellar population in the central 6.6´ × 6.6´ region of the ultra-deep (1Msec) Chandra Galactic field - the “Chandra bulge field” (CBF) approximately 1.5 degrees away from the Galactic Center - using the Hubble Space Telescope ACS/WFC blue (F435W) and red (F625W) images. We mainly focus on the behavior of red clump giants - a distin…
An AzTEC 1.1-mm survey for ULIRGs in the field of the Galaxy Cluster MS0451.6-0305
Ivison, R. J.; Yun, M. S.; Smail, Ian +17 more
We have undertaken a deep (σ ~ 1.1 mJy) 1.1-mm survey of the z = 0.54 cluster MS0451.6-0305 using the AzTEC camera on the James Clerk Maxwell Telescope. We detect 36 sources with signal-to-noise ratio (S/N) >= 3.5 in the central 0.10 deg2 and present the AzTEC map, catalogue and number counts. We identify counterparts to 18 sources (…
Upper limits on Titan's magnetic moment and implications for its interior
Russell, C. T.; Wei, H. Y.; Dougherty, M. K. +2 more
Measurements from the Cassini spacecraft reveal a largely magnetized ionosphere of Titan whose low-altitude fields could be from the interior of Titan or from penetrating external fields. We use the Cassini magnetic field measurements obtained during 25 Titan flybys to examine the upper limit of Titan's internal magnetic moment. The radial compone…
Energy Deposition Processes in Titan's Upper Atmosphere and Its Induced Magnetosphere
Hartle, R. E.; Dandouras, Iannis; Coates, Andrew +4 more
Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes~1,200 km but which can extend down to ~400 km, while the plasma…
Correlated optical and X-ray variability in CTTS. Indications of absorption-modulated emission
Micela, G.; Favata, F.; Flaccomio, E. +1 more
Aims: Optical and X-ray emission from classical T Tauri stars (CTTSs) has long been known to be highly variable. Our long, uninterrupted optical observation of the NGC 2264 region with CoRoT [The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programs, Austria, B…
Solar wind origins in coronal holes and in the quiet Sun
Tu, C. -Y.; Marsch, E.; Tian, H. +1 more
Coronal hole (CH) and the quiet Sun (QS) are considered to account for sources of fast and slow solar wind streams, respectively. The differences between the solar wind streams flowing out from the CH and the QS are thought to be related with different plasma generation and acceleration mechanisms in the respective source regions. Here we review r…