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When galaxies collide: understanding the broad absorption-line radio galaxy 4C +72.26
Jarvis, M. J.; Swinbank, A. M.; Rawlings, S. +2 more
We present a range of new observations of the `broad absorption-line radio galaxy' 4C +72.26 (z ~ 3.5), including sensitive rest-frame ultraviolet integral field spectroscopy using the Gemini/GMOS-N instrument and Subaru/CISCO K-band imaging and spectroscopy. We show that 4C +72.26 is a system of two vigorously star-forming galaxies superimposed a…
Quantifying the importance of ram-pressure stripping in a galaxy group at 100 Mpc
Croston, J. H.; Freeland, E.; Sengupta, C.
We examine two members of the NGC 4065 group of galaxies: a bent-double (aka wide angle tail) radio source and an H I-deficient spiral galaxy. Models of the X-ray-emitting intragroup gas and the bent-double radio source, NGC 4061, are used to probe the density of intergalactic gas in this group. H I observations reveal an asymmetric, truncated dis…
Quasar radio-loudness and the elliptical core problem
Hamilton, Timothy S.
The dichotomy between radio-loud and radio-quiet quasi-stellar objects (QSOs) is not simply one of host morphology. While spiral galaxies almost exclusively host radio-quiet QSOs, ellipticals can host either radio-louds or radio-quiets. We find that a combination of accretion rate and host scale determines which type of QSO a given elliptical gala…
IMF, SFR and stellar depletion in the local Galactic plane, based on improved Hipparcos samples of single stars
Schröder, K. -P.; Dawson, S. A.
We have used the recently reduced Hipparcos data and the Washington Double Star catalogue to derive two volume- and magnitude-limited samples of single stars in the Galactic plane. The star count method has been used to compare synthetic to empirical samples of stars within both the main sequence and the evolved regions of the Hertzsprung-Russell …
Ultraviolet study of the active interacting binary star R Arae using archival IUE data
Sahade, Jorge; Guinan, Edward F.; Reed, Phillip A. +7 more
The eclipsing and strongly interacting binary star system R Arae (HD 149730) is in a very active and very short-lived stage of its evolution. R Ara consists of a B9V primary and an unknown secondary. We have collected the International Ultraviolet Explorer (IUE) archival data on R Ara, with most of the data being studied for the first time. There …
X-ray emission characteristics of two Wolf-Rayet binaries: V444 Cyg and CD Cru
Pandey, J. C.; Singh, K. P.; Kumar, Brijesh +2 more
Using data from observations made with XMM-Newton, we present an X-ray analysis of two Wolf-Rayet (WR) binaries: V444 Cyg and CD Cru. The X-ray light curves show the phase-locked variability in both binaries, where the flux increased by a factor of ~2 for V444 Cyg and ~1.5 for CD Cru, from minimum to maximum. The maximum luminosities in the 0.3-7.…
A joint Chandra and XMM-Newton view of Abell 3158: a massive off-centre cool gas clump as a robust diagnostic of a merger stage
Xu, Haiguang; Zhang, Zhongli; Gu, Liyi +5 more
In previous works, the nearby galaxy cluster Abell 3158 was reported to possess a relatively regular, relaxed morphology in the X-ray band. By analysing the Chandra and XMM-Newton archived data of Abell 3158, we have identified a bow-edge-shaped discontinuity in the X-ray surface brightness distribution about 120h-171 kpc wes…
A far-ultraviolet variability survey of the globular cluster M80
Knigge, C.; Long, K. S.; Zurek, D. R. +2 more
We have searched for variable sources in the core region of M80, using far-ultraviolet (FUV) data taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. We found three sources that exhibit strong signs of variability in our data. Among these is source TDK1, which we believe to be an RRLyrae star that reached maximum bright…
Cepheid period-luminosity relation from the AKARI observations
Onaka, Takashi; Ita, Yoshifusa; Ngeow, Chow-Choong +3 more
In this paper, we derive the period-luminosity (P-L) relation for Large Magellanic Cloud (LMC) Cepheids based on mid-infrared AKARI observations. AKARI's Infrared Camera sources were matched to the Optical Gravitational Lensing Experiment-III (OGLE-III) LMC Cepheid catalogue. Together with the available I-band light curves from the OGLE-III catalo…
Infrared identification of 4U1323-619 revisited
Zolotukhin, Ivan Yu.; Revnivtsev, Mikhail G.; Shakura, Nikolai I.
We re-examine the infrared counterpart of the dipping low-mass X-ray binary 4U1323-619. New X-ray data available from the XMM and Chandra observatories combined with archival infrared observations from the European Southern Observatory 3.6-m New Technology Telescope allow us to define a new possible counterpart. We present here its photometric pro…