Search Publications
The Tight Relation between X-Ray and Ultraviolet Luminosity of Quasars
Lusso, E.; Risaliti, G.
The observed relation between the soft X-ray and the optical-ultraviolet emission in active galactic nuclei (AGNs) is nonlinear and it is usually parametrized as a dependence between the logarithm of the monochromatic luminosity at 2500 Å and at 2 keV. Previous investigations have found that the dispersion of this relation is rather high (∼0.35-0.…
Discovery of a Galaxy Cluster with a Violently Starbursting Core at z = 2.506
Daddi, Emanuele; Tan, Qinghua; Liu, Daizhong +17 more
We report the discovery of a remarkable concentration of massive galaxies with extended X-ray emission at z spec = 2.506, which contains 11 massive (M * ≳ 1011 M ⊙) galaxies in the central 80 kpc region (11.6σ overdensity). We have spectroscopically confirmed 17 member galaxies with 11 from CO and the re…
Host-galaxy Properties of 32 Low-redshift Superluminous Supernovae from the Palomar Transient Factory
Gal-Yam, A.; Filippenko, A. V.; Nugent, P. E. +9 more
We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies of all superluminous supernovae (SLSNe) discovered by the Palomar Transient Factory prior to 2013 and derive measurements of their luminosities, star formation rates, stellar masses, and gas-phase metallicities. We find that Type I (hydrogen-poor) SLSNe (…
The Hα surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae
Frew, David J.; Parker, Q. A.; Bojičić, I. S.
Measuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the Hα surface brightness-radius or SHα-r relation, which addresses this problem. We developed this relation from a critically evaluated sample of primary …
Planck 2015 results. XXV. Diffuse low-frequency Galactic foregrounds
Kneissl, R.; Miville-Deschênes, M. -A.; Boulanger, F. +237 more
We discuss the Galactic foreground emission between 20 and 100 GHz based on observations by Planck and WMAP. The total intensity in this part of the spectrum is dominated by free-free and spinning dust emission, whereas the polarized intensity is dominated by synchrotron emission. The Commander component-separation tool has been used to separate t…
The Macronova in GRB 050709 and the GRB-macronova connection
Li, Xiang; Jin, Zhi-Ping; Covino, Stefano +6 more
GRB 050709 was the first short Gamma-ray Burst (sGRB) with an identified optical counterpart. Here we report a reanalysis of the publicly available data of this event and the discovery of a Li-Paczynski macronova/kilonova that dominates the optical/infrared signal at t>2.5 days. Such a signal would arise from 0.05 r-process material launched by…
ALMA Imaging and Gravitational Lens Models of South Pole Telescope—Selected Dusty, Star-Forming Galaxies at High Redshifts
Béthermin, M.; Weiss, A.; Greve, T. R. +18 more
The South Pole Telescope has discovered 100 gravitationally lensed, high-redshift, dusty, star-forming galaxies (DSFGs). We present 0.″5 resolution 870 µ {{m}} Atacama Large Millimeter/submillimeter Array imaging of a sample of 47 DSFGs spanning z=1.9{--}5.7, and construct gravitational lens models of these sources. Our visibility-based lens…
A global look at X-ray time lags in Seyfert galaxies
Fabian, A. C.; Reynolds, C. S.; Uttley, P. +4 more
X-ray reverberation, where light-travel time delays map out the compact geometry around the inner accretion flow in supermassive black holes, has been discovered in several of the brightest, most variable and well-known Seyfert galaxies. In this work, we expand the study of X-ray reverberation to all Seyfert galaxies in the XMM-Newton archive abov…
The Evolution of Normal Galaxy X-Ray Emission through Cosmic History: Constraints from the 6 MS Chandra Deep Field-South
Lehmer, B. D.; Hornschemeier, A. E.; Yukita, M. +17 more
We present measurements of the evolution of normal-galaxy X-ray emission from z\quad ≈ 0-7 using local galaxies and galaxy samples in the ≈6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations…
The Lyman-Continuum Photon Production Efficiency ξ ion of z ∼ 4-5 Galaxies from IRAC-based Hα Measurements: Implications for the Escape Fraction and Cosmic Reionization
Bouwens, R. J.; Franx, M.; Labbé, I. +5 more
Galaxies represent one of the preferred candidate sources to drive the reionization of the universe. Even as gains are made in mapping the galaxy UV luminosity density to z\gt 6, significant uncertainties remain regarding the conversion to the implied ionizing emissivity. The relevant unknowns are the Lyman-continuum (LyC) photon production effici…