Search Publications
A mechanism for comet surface collapse as observed by Rosetta on 67P/Churyumov-Gerasimenko
Sierks, H.; Prialnik, D.
We explore a possible mechanism that may explain sudden depressions of surface areas on a comet nucleus, as suggested by observations of the Rosetta mission on comet 67P/Churyumov-Gerasimenko (hereafter, 67P/C-G). Assuming the area is covered by a thin, compact dust layer of low permeability to gas flow compared to deeper, porous layers, gas can a…
Energy-dependent variability of the bare Seyfert 1 galaxy Ark 120
Dewangan, Gulab C.; McHardy, I. M.; Mallick, Labani +1 more
We present results from a detailed spectral-timing analysis of a long ∼486 ks XMM-Newton observation of the bare Seyfert 1 galaxy Ark 120 which showed alternating diminution and increment in the 0.3-10 keV X-ray flux over four consecutive orbits in 2014. We study the energy-dependent variability of Ark 120 through broad-band X-ray spectroscopy, fr…
X-rays from Green Pea analogues
Kaaret, P.; Brorby, M.
X-ray observations of two metal-deficient luminous compact galaxies (LCG; SHOC 486 and SDSS J084220.94+115000.2) with properties similar to the so-called Green Pea galaxies were obtained using the Chandra X-ray Observatory. Green Pea galaxies are relatively small, compact (a few kpc across) galaxies that get their green colour from strong [O III] …
Spatially resolved analysis of superluminous supernovae PTF 11hrq and PTF 12dam host galaxies
Perley, Daniel A.; Lunnan, Ragnhild; Kim, Sam +12 more
Superluminous supernovae (SLSNe) are the most luminous supernovae in the Universe. They are found in extreme star-forming galaxies and are probably connected with the death of massive stars. One hallmark of very massive progenitors would be a tendency to explode in very dense, UV-bright and blue regions. In this paper, we investigate the resolved …
K2-113: a dense hot-Jupiter transiting a solar analogue
Jordán, Andrés; Espinoza, Néstor; Brahm, Rafael +8 more
We present the discovery of K2-113, a dense hot-Jupiter discovered using photometry from Campaign 8 of the Kepler-2 (K2) mission and high-resolution spectroscopic follow-up obtained with the FEROS spectrograph. The planet orbits a V = 13.68 solar analogue in a P=5.817 60^{+0.000 03}_{-0.000 03} d orbit, and has a radius of 0.93^{+0.10}_{-0.07}R_J …
Origin of X-rays in the low state of the FSRQ 3C 273: evidence of inverse Compton emission
Gupta, Alok C.; Wiita, Paul J.; Dewangan, Gulab C. +2 more
We analyse the 2.5-10 keV X-ray spectra of the luminous quasar 3C 273 and simultaneous observations in UV wavelengths from XMM-Newton between 2000 and 2015. The lowest flux level ever was observed in 2015. The continuum emission from 3C 273 is generally best described by an absorbed power-law but during extremely low states the addition of fluores…
Identification of IGR J01217-7257 with the transient SMC pulsar XTE J0119-731 (SXP 2.16) using XMM-Newton
Haberl, F.; Vasilopoulos, G.; Maggi, P.
The transient IGR J01217-7257 in the Small Magellanic Cloud was found to be in a new outburst during INTEGRAL observations. We triggered an XMM-Newton target of opportunity observation near outburst maximum, which lead to the discovery of X-ray pulsations with a period of 2.165 s. This period is very similar to that detected from XTE J0119-731, su…
The challenging task of determining star formation rates: the case of a massive stellar burst in the brightest cluster galaxy of Phoenix galaxy cluster
McDonald, M.; Bruzual, Gustavo; Mittal, Rupal +1 more
Star formation in galaxies at the centre of cooling-flow galaxy clusters is an important phenomenon in the context of formation and evolution of massive galaxies in the Universe. Yet, star formation rates (SFRs) in such systems continue to be elusive. We use our Bayesian-motivated spectral energy distribution (SED)-fitting code, BAYESCOOL, to esti…
Trapping mechanism of O2 in water ice as first measured by Rosetta spacecraft
Bar-Nun, Akiva; Laufer, Diana; Ninio Greenberg, Adi
One of the most surprising measurements of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument on the comet 67P/Churyumov-Gerasimenko was the detection of O2 along with N2 and noble gases which were measured for the first time in comets, along with the major constituents, water, CO, and CO2<…
The effect of the environment on the structure, morphology and star formation history of intermediate-redshift galaxies
Schrabback, Tim; Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo +4 more
With the aim of understanding the effect of the environment on the star formation history and morphological transformation of galaxies, we present a detailed analysis of the colour, morphology and internal structure of cluster and field galaxies at 0.4 ≤ z ≤ 0.8. We use the Hubble Space Telescope data for over 500 galaxies from the ESO Distant Clu…