Search Publications
X-ray absorption variability in NGC 4507
Elvis, Martin; Risaliti, Guido; Nardini, Emanuele +5 more
We present a complete spectral analysis of an XMM-Newton and Chandra campaign of the obscured AGN in NGC 4507, consisting of six observations spanning a period of six months, ranging from 2010 June to December. We detect strong absorption variability on time-scales between 1.5 and 4 months, suggesting that the obscuring material consists of gas cl…
An outburst scenario for the X-ray spectral variability in 3C 111
Reynolds, C. S.; García, J.; Lohfink, A. +2 more
We present a combined Suzaku and Swift BAT broad-band E = 0.6-200 keV spectral analysis of three 3C 111 observations obtained in 2010. The data are well described with an absorbed power-law continuum and a weak (R ≃ 0.2) cold reflection component from distant material. We constrain the continuum cutoff at EC ≃ 150-200 keV, which is in a…
The spatial extent and distribution of star formation in 3D-HST mergers at z ∼ 1.5
Maseda, Michael V.; Schmidt, Kasper B.; Franx, Marijn +14 more
We present an analysis of the spatial distribution of star formation in a sample of 60 visually identified galaxy merger candidates at z > 1. Our sample, drawn from the 3D-HST survey, is flux limited and was selected to have high star formation rates based on fits of their broad-band, low spatial resolution spectral energy distributions. It inc…
XMM-Newton observation of the highly magnetized accreting pulsar Swift J045106.8-694803: evidence of a hot thermal excess
Bartlett, E. S.; Coe, M. J.; Ho, W. C. G.
Several persistent, low-luminosity (LX ∼ 1034 erg s-1), long-spin-period (P > 100 s) high-mass X-ray binaries have been reported with blackbody components with temperatures >1 keV. These hot thermal excesses have correspondingly small emitting regions (<1 km2) and are attributed to the neutron s…
Probing the extended gaseous regions of M31 with quasar absorption lines
Turnshek, David A.; Rao, Sandhya M.; York, Donald G. +4 more
We present Hubble Space Telescope Cosmic Origins Spectrograph spectra of 10 quasars located behind M31, selected to investigate the properties of gas associated with its extended disc and high-velocity clouds (HVCs). The sightlines have impact parameters ranging between b = 13 and 112 kpc. No absorption is detected in the four sightlines selected …
An O2If* star found in isolation in the backyard of NGC 3603.
Roman-Lopes, A.
In this Letter, we communicate the identification of a new Galactic O2If* star (MTT 68) isolated at a projected linear distance of 3 pc from the centre of the starburst cluster NGC 3603. From its optical photometry, I computed a bolometric luminosity MBol = -10.7, which corresponds to a total stellar luminosity of 1.5 × 106 L…
The detection of FIR emission from high-redshift star-forming galaxies in the ECDF-S
Bremer, M. N.; Lehnert, M. D.; Davies, L. J. M. +1 more
We have used the Large Apex Bolometer Camera Survey of the Extended Chandra Deep Field South to investigate rest-frame far-infrared (FIR) emission from typical star-forming systems (Lyman-break galaxies, LBGs, and Lyman α emitters, LAEs) at redshift 3, 4, 4.5 and 5 (922, 68, 46 and 20 sources, respectively). We initially concentrate on LBGs at z ∼…
Characterizing shock waves in molecular outflow sources: the interpretation of Herschel and Spitzer observations of NGC 1333 IRAS 4B
Pineau des Forêts, G.; Flower, D. R.
We have computed C- and J-type models of shock waves in molecular outflow sources. In addition to the (optically thin) emission line spectrum of molecular hydrogen, the spectra of CO, OH, SiO, H2O and NH3 were computed by means of the large velocity gradient approximation. We find that the intensities of the OH lines are part…
Alignment of the angular momentum vectors of planetary nebulae in the Galactic Bulge
Zijlstra, A. A.; Rees, B.
We use high-resolution Hα images of 130 planetary nebulae (PNe) to investigate whether there is a preferred orientation for PNe within the Galactic Bulge. The orientations of the full sample have a uniform distribution. However, at a significance level of 0.01, there is evidence for a non-uniform distribution for those PNe with evident bipolar mor…
Star formation and dust heating in the FIR bright sources of M83
Boquien, M.; Cooray, A.; Lebouteiller, V. +16 more
We investigate star formation and dust heating in the compact far-infrared (FIR) bright sources detected in the Herschel maps of M83. We use the source extraction code GETSOURCES to detect and extract sources in the FIR, as well as their photometry in the mid-infrared and Hα. By performing infrared spectral energy distribution fitting and applying…