Search Publications
The starburst-active galactic nucleus connection in the merger galaxy Mrk 938: an infrared and X-ray view
Altieri, B.; Valtchanov, I.; Esquej, P. +14 more
Mrk 938 is a luminous infrared (IR) galaxy in the local Universe believed to be the remnant of a galaxy merger. It shows a Seyfert 2 nucleus and intense star formation according to optical spectroscopic observations. We have studied this galaxy using new Herschel far-IR imaging data in addition to archival X-ray, UV, optical, near-IR and mid-IR da…
A multiwavelength survey of AGN in massive clusters: AGN detection and cluster AGN fraction
Sarajedini, Vicki L.; Klesman, Alison J.
We aim to study the effect of environment on the presence and fuelling of active galactic nuclei (AGNs) in massive galaxy clusters. We explore the use of different AGN detection techniques with the goal of selecting AGN across a broad range of luminosities, AGN/host galaxy flux ratios and obscuration levels. From a sample of 12 galaxy clusters at …
In the whirlpool's coils: tracing substructure from combined optical/X-ray data in the galaxy cluster A1300
Finoguenov, A.; Böhringer, H.; Ziparo, F. +3 more
Structure formation is thought to act via hierarchical mergers and accretion of smaller systems driven by gravity, with dark matter dominating the gravitational field. Combining X-ray and optical imaging and spectroscopy provides a powerful approach to the study of the cluster dynamics and mass assembly history. The ROSAT-ESO Flux Limited X-ray (R…
Hα star formation rates in massive galaxies at z∼ 1
Weiner, Benjamin J.; Conselice, Christopher J.; Bauer, Amanda E. +4 more
We present a near-infrared spectroscopic study of a stellar mass selected sample of galaxies at z∼ 1 utilizing the Long-slit Intermediate Resolution Infrared Spectrograph multi-object spectrograph on the William Herschel Telescope. We detect continuum, and the Hα line for our sample, which is one of the better direct tracers of star formation in e…
Spectral comparison of weak short bursts to the persistent X-rays from the magnetar 1E 1547.0-5408 in its 2009 outburst
Sakamoto, T.; Enoto, T.; Makishima, K. +1 more
In 2009 January, the 2.1-s anomalous X-ray pulsar 1E 1547.0-5408 evoked intense burst activity. A follow-up Suzaku observation on January 28 recorded enhanced persistent emission in both soft and hard X-rays. Through a reanalysis of the same Suzaku data, 18 short bursts were identified in the X-ray events recorded by the Hard X-ray Detector (HXD) …
Discovery of multiple shells around the planetary nebula IC 418
Guerrero, M. A.; Ramos-Larios, G.; Bravo-Alfaro, H. +3 more
We have analysed optical, near- and mid-IR images of the bright planetary nebula (PN) IC 418. These images probe unambiguously for the first time a number of low surface brightness structures and shells around the bright main nebula, including radial filaments or rays, a system of three concentric rings and two detached haloes with sizes ∼150 arcs…
A multiwavelength survey of NGC 6752: X-ray counterparts, two new dwarf novae and a core-collapsed radial profile
Maccarone, T. J.; Knigge, C.; Sarajedini, A. +6 more
We present the results of a multiwavelength (far-ultraviolet to I band) survey of the stellar populations of the globular cluster NGC 6752, using Space Telescope Imaging Spectrograph (STIS), Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We have confirmed that two previously identified catacly…
Separating the BL Lac and cluster X-ray emissions in Abell 689 with Chandra
Birkinshaw, M.; Worrall, D. M.; Maughan, B. J. +2 more
We present the results of a Chandra observation of the galaxy cluster Abell 689 (z = 0.279). Abell 689 is one of the most luminous clusters detected in the ROSAT All Sky Survey (RASS), but was flagged as possibly including significant point source contamination. The small point spread function of the Chandra telescope allows us to confirm this and…
Constraints on sterile neutrino dark matter from XMM-Newton observations of M33
Paolillo, M.; Longo, G.; Borriello, E. +2 more
Using archival XMM-Newton observations of the diffuse and unresolved components' emission in the inner disc of M33, we exclude the possible contribution from narrow line emission in the energy range 0.5-5 keV more intense than 10-6-10-5 erg s-1. Under the hypothesis that sterile neutrinos constitute the majority of…
Highly ionized collimated outflow from HE 0238-1904
Savage, B. D.; Narayanan, A.; Dewangan, G. C. +3 more
We present a detailed analysis of a highly ionized, multiphased and collimated outflowing gas detected through O V, O VI, Ne VIII and Mg X absorption associated with the QSO HE 0238-1904 (zem≃ 0.629). Based on the similarities in the absorption-line profiles and estimated covering fractions, we find that the O VI and Ne VIII absorption …