Search Publications

Newborn spheroids at high redshift: when and how did the dominant, old stars in today's massive galaxies form?

Ryan, R. E.; O'Connell, R. W.; Dekel, A. +10 more

We study ∼330 massive (M_* > 10^9.5 M_⊙), newborn spheroidal galaxies (SGs) around the epoch of peak star formation (1 < z < 3) to explore the high-redshift origin of SGs and gain insight into when and how the old stellar populations that dominate today's Universe formed. The sample is drawn from the Hubble S…

The flux-dependent X-ray time lags in NGC 4051

Vaughan, S.; Uttley, P.; Alston, W. N.

We present an analysis of the X-ray time lags for the highly variable Seyfert 1 galaxy NGC 4051, based on a series of XMM-Newton observations taken in 2009. We investigate the Fourier frequency dependent time lags in the light curves between the 0.3-1.0 keV and 2.0-5.0 keV energy bands as a function of source flux, including simultaneous modelling…

GAMA/H-ATLAS: The Dust Opacity-Stellar Mass Surface Density Relation for Spiral Galaxies

Cooray, A.; De Zotti, G.; Baes, M. +32 more

We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust, τ ^f_B, and the stellar mass surface density, µ_*, of nearby (z <= 0.13) spiral galaxies: {log}(τ ^{f}_{B}) = 1.12(+/- 0.11) \cdot {log}({µ _{*}}/{{M}_{⊙ } {kpc}^{-2}}) - 8.6(+/- 0.8). This relation was derived f…

Suzaku X-Ray Observations of the Accreting NGC 4839 Group of Galaxies and a Radio Relic in the Coma Cluster

Sarazin, Craig L.; Inoue, Susumu; Akamatsu, Hiroki +3 more

Based on Suzaku X-ray observations, we studied the hot gas around the NGC 4839 group of galaxies and a radio relic in the outskirts of the Coma cluster. We found a gradual decline in the gas temperature from 5 keV around NGC 4839 to 3.6 keV at the radio relic, across which there is a further, steeper drop down to 1.5 keV. This drop as well as the …

Shock Excited Molecules in NGC 1266: ULIRG Conditions at the Center of a Bulge-dominated Galaxy

Rigopoulou, D.; Murphy, E. J.; Armus, L. +28 more

We investigate the far infrared (IR) spectrum of NGC 1266, a S0 galaxy that contains a massive reservoir of highly excited molecular gas. Using the Herschel Fourier Transform Spectrometer, we detect the ¹²CO ladder up to J = (13-12), [C I] and [N II] lines, and also strong water lines more characteristic of UltraLuminous IR Galaxies (UL…

Hectospec and Hydra Spectra of Infrared Luminous Sources in the AKARI North Ecliptic Pole Survey Field

Kim, Seong Jin; Papovich, Casey; Weiner, Benjamin J. +7 more

We present spectra of 1796 sources selected in the AKARI North Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and WIYN/Hydra, for which we measure 1645 redshifts. We complemented the generic flux-limited spectroscopic surveys at 11 µm and 15 µm, with additional sources selected based on the MIR and optical colors. In MMT/…

Precipitation-induced surface brightenings seen on Titan by Cassini VIMS and ISS

Nicholson, Philip D.; Sotin, Christophe; Barnes, Jason W. +17 more

Constraints on the nature of CID-42: recoil kick or supermassive black hole pair?

Elvis, Martin; Loeb, Abraham; Blecha, Laura +1 more

The galaxy CXOC J100043.1+020637, also known as CID-42, is a highly unusual object. As an apparent galaxy merger remnant, it displays signatures of both an inspiraling, kiloparsec-scale active galactic nucleus (AGN) pair and of a recoiling AGN with a kick velocity of ≳ 1300 km s^-1. Among recoiling AGN candidates, CID-42 alone has both s…

Evidence for Hot Fast Flow above a Solar Flare Arcade

Shimizu, T.; Hara, H.; Watanabe, T. +3 more

Solar flares are one of the main forces behind space weather events. However, the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in the corona where hot fast flows are created. Some imaging or spectroscopic observations have indicated the pre…

The Spectrally Resolved Lyα Emission of Three Lyα-selected Field Galaxies at z ~ 2.4 from the HETDEX Pilot Survey

Finkelstein, Steven L.; Kollmeier, Juna A.; Blanc, Guillermo A. +11 more

We present new results on the spectrally resolved Lyα emission of three Lyα-emitting field galaxies at z ~ 2.4 with high Lyα equivalent width (>100 Å) and Lyα luminosity (~10⁴³ erg s^-1). At 120 km s^-1 (FWHM) spectral resolution, the prominent double-peaked Lyα profile straddles the systemic velocity, where the v…