Search Publications
The He II Proximity Effect and The Lifetime of Quasars
Worseck, G.; Hennawi, J. F.; McQuinn, M. +1 more
The lifetime of quasars is fundamental for understanding the growth of supermassive black holes, and is an important ingredient in models of the reionization of the intergalactic medium (IGM). However, despite various attempts to determine quasar lifetimes, current estimates from a variety of methods are uncertain by orders of magnitude. This work…
The SHARDDS survey: First resolved image of the HD 114082 debris disk in the Lower Centaurus Crux with SPHERE
Pueyo, Laurent; Ertel, Steve; Boccaletti, Anthony +17 more
We present the first resolved image of the debris disk around the 16 ± 8 Myr old star, HD 114082. The observation was made in the H-band using the SPHERE instrument. The star is at a distance of 92 ± 6 pc in the Lower Centaurus Crux association. Using a Markov chain Monte Carlo analysis, we determined that the debris is likely in the form of a dus…
Discovery of an Extremely Wide-angle Bipolar Outflow in AFGL 5142
Kim, Kee-Tae; Lee, Jeong-Eun; Li, Di +12 more
Most bipolar outflows are associated with individual young stellar objects and have small opening angles. Here we report the discovery of an extremely wide-angle (∼180°) bipolar outflow (“EWBO”) in a cluster forming region AFGL 5142 from low-velocity emission of the HCN (3-2) and HCO+ (3-2) lines. This bipolar outflow is along a north-w…
Another look at distortions of the Cosmic Microwave Background spectrum
Negrello, M.; Lapi, A.; De Zotti, G. +2 more
We review aspects of Cosmic Microwave Background (CMB) spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to …
The dust environment of comet 67P/Churyumov-Gerasimenko from Rosetta OSIRIS and VLT observations in the 4.5 to 2.9 AU heliocentric distance range inbound
Jorda, L.; Lamy, P. L.; Lara, L. M. +51 more
Context. The ESA Rosetta spacecraft, currently orbiting around comet 67P/Churyumov-Gerasimenko, has already provided in situ measurements of the dust grain properties from several instruments,particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the…
Origin of the local structures at the Philae landing site and possible implications on the formation and evolution of 67P/Churyumov-Gerasimenko
Bibring, J. -P.; Gondet, B.; Langevin, Y. +7 more
In situ images of the 67P/Churyumov-Gerasimenko nucleus acquired by the CIVA cameras on-board PHILAE revealed a rough landscape dominated by consolidated materials. These data provide a unique view to constrain the past and present conditions prevailing at the surface of the comet. A quantitative analysis of microscopic structures (fractures and p…
Study of Swift/Bat Selected Low-luminosity Active Galactic Nuclei Observed with Suzaku
Ueda, Yoshihiro; Kawamuro, Taiki; Terashima, Yuichi +2 more
We systematically analyze the broadband (0.5-200 keV) X-ray spectra of hard X-ray (>10 keV) selected local low-luminosity active galactic nuclei (LLAGNs) observed with Suzaku and Swift/BAT. The sample consists of 10 LLAGNs detected with Swift/BAT with intrinsic 14-195 keV luminosities smaller than 1042 erg s-1 available in…
Light-curve Analysis of Neon Novae
Kato, Mariko; Hachisu, Izumi
We analyzed light curves of five neon novae, QU Vul, V351 Pup, V382 Vel, V693 CrA, and V1974 Cyg, and determined their white dwarf (WD) masses and distance moduli on the basis of theoretical light curves composed of free-free and photospheric emission. For QU Vul, we obtained a distance of d ∼ 2.4 kpc, reddening of E(B - V) ∼ 0.55, and WD mass of …
Differential cosmic expansion and the Hubble flow anisotropy
Wiltshire, David L.; Bolejko, Krzysztof; Nazer, M. Ahsan
The Universe on scales 01-100 h-1Mpc is dominated by a cosmic web of voids, filaments, sheets and knots of galaxy clusters. These structures participate differently in the global expansion of the Universe: from non-expanding clusters to the above average expansion rate of voids. In this paper we characterize Hubble expansion anisotropie…
The Magnetic Classification of Solar Active Regions 1992-2015
Jaeggli, S. A.; Norton, A. A.
The purpose of this Letter is to address a blindspot in our knowledge of solar active region (AR) statistics. To the best of our knowledge, there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all ARs reported in the daily…