Search Publications
A Compton-thick active galactic nucleus powering the hyperluminous infrared galaxy IRAS 00182-7112
Nandra, K.; Iwasawa, K.
We present X-ray observations of the hyperluminous infrared galaxy (HLIRG) IRAS 00182- 7112 obtained using the XMM-Newton EPIC camera. A luminous hard X-ray source coincident with the nucleus is revealed, along with weaker soft X-ray emission which may be extended or offset from the hard emission. The EPIC spectrum is extremely flat and shows Fe K…
The galaxy luminosity-size relation and selection biases in the Hubble Ultra Deep Field
Cameron, E.; Driver, S. P.
We use the Hubble Ultra Deep Field to study the galaxy luminosity-size (M-Re) distribution. With a careful analysis of selection effects due to both detection completeness and measurement reliability, we identify bias-free regions in the M-Re plane for a series of volume-limited samples. By comparison to a nearby survey also …
Absolute magnitudes of OB and Be stars based on Hipparcos parallaxes - III
Wegner, W.
The absolute visual magnitudes, MV, of A-M stars are based on calculated Hipparcos trigonometric parallaxes. The sample used consists of 30986 unreddened and reddened A-M stars in luminosity classes Ia, Iab, Ib, II, III, IV and V. The colour excesses of the reddened stars were calculated using the mean colour indices, according to the S…
A new constraint for gamma-ray burst progenitor mass
Fruchter, Andrew S.; Larsson, Josefin; Levan, Andrew J. +1 more
Recent comparative observations of long-duration gamma-ray bursts (LGRBs) and core collapse supernova (cc SN) host galaxies demonstrate that these two, highly energetic transient events are distributed very differently upon their hosts. LGRBs are much more concentrated on their host galaxy light than cc SN. Here we explore the suggestion that this…
The dark haloes of early-type galaxies in low-density environments: XMM-Newton and Chandra observations of NGC 57, 7796 and IC 1531
Ponman, Trevor J.; O'Sullivan, Ewan; Sanderson, Alastair J. R.
We present analysis of Chandra and XMM-Newton observations of three early-type galaxies, NGC 57, 7796 and IC 1531. All three are found in very low-density environments, and appear to have no neighbours of comparable size. NGC 57 has a halo of kT ~ 0.9 keV, solar metallicity gas, while NGC 7796 and IC 1531 both have ~0.55 keV, 0.5-0.6Zsolar
An HI threshold for star cluster formation in tidal debris
Charlton, Jane C.; Maybhate, Aparna; English, Jayanne +4 more
Superstar clusters are young, compact star clusters found in the central regions of interacting galaxies. Recently, they have also been reported to preferentially form in certain tidal tails, but not in others. In this paper, we have used 21-cm HI maps and the Hubble Space Telescope Wide Field Planetary Camera 2 images of eight tidal tail regions …
IRAS 13197-1627 has them all: Compton-thin absorption, photoionized gas, thermal plasmas and a broad Fe line
Cappi, M.; Ponti, G.; Dadina, M. +2 more
We report results from the XMM-Newton observation of IRAS 13197-1627, a luminous infrared (IR) galaxy with a Seyfert 1.8 nucleus. The hard X-ray spectrum is steep (Γ ~ 2.5) and is absorbed by Compton-thin (NH ~ 4 × 1023 cm-2) neutral gas. We detect a Fe Kα emission line at 6.4 keV, consistent with transmission thro…
A multiwavelength map of the nuclear region of NGC 7582
Guainazzi, Matteo; Bianchi, Stefano; Piconcelli, Enrico +1 more
We have performed a detailed analysis of the Chandra and Hubble Space Telescope (HST) images of the Seyfert 2 galaxy NGC 7582. The dust lane, as mapped by the HST near-infrared and optical images, strongly influences the morphology of the soft X-ray emission, being spatially coincident with excess of X-ray absorption. Two `hotspots', i.e. regions …
Integral-field spectroscopy of Centaurus A nucleus
Krajnović, Davor; Thatte, Niranjan; Sharp, Rob
We report integral-field spectroscopic observations with the Cambridge Infrared Panoramic Survey Spectrograph (CIRPASS) mounted on the Gemini South telescope of the nucleus of the nearby galaxy NGC 5128 (Centaurus A). We detect two-dimensional distributions of the following emission lines: [PII], [FeII] and Paschen β. We compare our observations w…
Extragalactic MeV γ-ray emission from cocoons of young radio galaxies
Kawakatu, N.; Kino, M.; Ito, H.
Strong γ-ray emission from cocoons of young radio galaxies is predicted for the first time. Considering the process of adiabatic injection of the shock dissipation energy and mass of the relativistic jet in active nuclei into the cocoon, while assuming thermalizing electron plasma interactions, we find that the thermal electron temperature of the …