Search Publications
Chandra observations of RX J1347.5-1145: the distribution of mass in the most X-ray-luminous galaxy cluster known
Fabian, A. C.; Allen, S. W.; Schmidt, R. W.
We present Chandra observations of RX J1347.5-1145, the most X-ray-luminous cluster of galaxies known. We report the discovery of a region of relatively hot, bright X-ray emission, located approximately 20 arcsec to the south-east of the main X-ray peak at a position consistent with the region of enhanced Sunyaev-Zel'dovich effect reported recentl…
The initial conditions of isolated star formation - V. ISOPHOT imaging and the temperature and energy balance of pre-stellar cores
Ward-Thompson, D.; André, P.; Kirk, J. M.
ISO data taken with the long-wavelength imaging photo-polarimeter ISOPHOT are presented of 18 pre-stellar cores at three far-infrared wavelengths, 90, 170 and 200µm. Most of the cores are detected clearly at 170 and 200µm, but only one is detected strongly at 90µm, indicating that mostly they are very cold, with typical temperatu…
Dissecting the Homunculus nebula around Eta Carinae with spatially resolved near-infrared spectroscopy
Smith, Nathan
Near-infrared emission lines are unique diagnostics of the geometry, structure, kinematics, and excitation of the circumstellar ejecta of η Carinae, and give clues to the nature of its wind. The infrared spectrum is a strong function of position in η Car's nebula, with a mix of intrinsic and reflected emission. Molecular hydrogen traces cool gas a…
The evolving accretion disc in the black hole X-ray transient XTE J1859+226
Chaty, S.; Cui, W.; Shrader, C. R. +2 more
We present HST, RXTE, and UKIRT observations of the broad-band spectra of the black hole X-ray transient XTE J1859+226 during the decline from its 1999-2000 outburst. Our UV spectra define the 2175-Å interstellar absorption feature very well and based on its strength we estimate E(B-V)=0.58+/-0.12. Hence we deredden our spectra and follow the evol…
An observational study of a magneto-acoustic wave in the solar corona
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +5 more
The Solar Eclipse Corona Imaging System (SECIS) observed a strong 6-s oscillation in an active region coronal loop, during the 1999 August 11 total solar eclipse. In the present paper we show that this oscillation is associated with a fast-mode magneto-acoustic wave that travels through the loop apex with a velocity of 2100 km s-1. We u…
Supernovae in deep Hubble Space Telescope galaxy cluster fields: cluster rates and field counts
Maoz, Dan; Sharon, Keren; Gal-Yam, Avishay
We have searched for high-redshift supernova (SN) candidates in multiple deep Hubble Space Telescope (HST ) archival images of nine galaxy cluster fields. We detect six apparent SNe, with 21.6<=I 814 <=28.4mag. There is roughly 1 SN per deep (I 814 >26mag), doubly-imaged WFPC2 cluster field. Two SNe are associated wi…
Maximum-entropy weak lens reconstruction: improved methods and application to data
Marshall, P. J.; Bridle, S. L.; Hobson, M. P. +1 more
We develop the maximum-entropy weak shear mass reconstruction method presented in earlier papers by taking each background galaxy image shape as an independent estimator of the reduced shear field and incorporating an intrinsic smoothness into the reconstruction. The characteristic length-scale of this smoothing is determined by Bayesian methods. …
The peculiar variable V838 Mon
Kimeswenger, S.; Lederle, C.; Schmeja, S. +1 more
V838 Mon underwent, after a first nova-like outburst in January and a usual decline, a second outburst after one month, and a third weak one again a month later. Moreover, a very small increase of the temperature at the beginning of April gives us a hint about a physical process with a period of one month. We obtained a BVRIC time-seque…
The percentage of stellar light re-radiated by dust in late-type Virgo Cluster galaxies
Tuffs, Richard J.; Popescu, Cristina C.
We show that the mean percentage of stellar light re-radiated by dust is ~30 per cent for the Virgo Cluster late-spirals measured with ISOPHOT by Tuffs et al. A strong dependence of this ratio with morphological type was found, ranging from typical values of ~15 per cent for early spirals to up to ~50 per cent for some late spirals. The extreme BC…
A new method for ISOCAM data reduction - II. Mid-infrared extragalactic source counts in the ELAIS Southern field
Pozzi, F.; Franceschini, A.; Serjeant, S. +5 more
We present the 15-µm extragalactic source counts from the Final Analysis Catalogue of the European Large Area ISO Survey (ELAIS) Southern hemisphere field S1, extracted using the Lari method. The large number of extragalactic sources (~350) detected over this area between about 0.5 and 100 mJy guarantee a high statistical significance of the…