Search Publications
No Overdensity of Lyman-Alpha Emitting Galaxies around a Quasar at z ∼ 5.7
Walter, F.; Decarli, R.; Overzier, R. +4 more
Bright quasars, observed when the universe was less than one billion years old (z > 5.5), are known to host massive black holes (∼109 M⊙) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations …
Red clump stars and Gaia: calibration of the standard candle using a hierarchical probabilistic model
Bovy, Jo; Leistedt, Boris; Hogg, David W. +1 more
Distances to individual stars in our own Galaxy are critical in order to piece together the nature of its velocity and spatial structure. Core helium burning red clump (RC) stars have similar luminosities, are abundant throughout the Galaxy and thus constitute good standard candles. We build a hierarchical probabilistic model to quantify the quali…
High-precision abundances of elements in Kepler LEGACY stars. Verification of trends with stellar age
Christensen-Dalsgaard, J.; Grundahl, F.; Slumstrup, D. +3 more
Context. A previous study of solar twin stars has revealed the existence of correlations between some abundance ratios and stellar age providing new knowledge about nucleosynthesis and Galactic chemical evolution.
Aims: High-precision abundances of elements are determined for stars with asteroseismic ages in order to test the solar twin relat…
Ultra-diffuse and Ultra-compact Galaxies in the Frontier Fields Cluster Abell 2744
van Dokkum, Pieter; Romanowsky, Aaron J.; Abraham, Roberto +3 more
We report the discovery of a large population of ultra-diffuse galaxies (UDGs) in the massive galaxy cluster Abell 2744 (z = 0.308) as observed by the Hubble Frontier Fields program. Since this cluster is ∼5 times more massive than Coma, our observations allow us to extend 0.7 dex beyond the high-mass end of the relationship between UDG abundance …
Updating the (supermassive black hole mass)-(spiral arm pitch angle) relation: a strong correlation for galaxies with pseudobulges
Graham, Alister W.; Davis, Benjamin L.; Seigar, Marc S.
We have conducted an image analysis of the (current) full sample of 44 spiral galaxies with directly measured supermassive black hole (SMBH) masses, MBH, to determine each galaxy's logarithmic spiral arm pitch angle, ϕ. For predicting black hole masses, we have derived the relation: log (MBH/M⊙) = (7.01 ± 0.07) - (…
Galactic masers: Kinematics, spiral structure and the disk dynamic state
Dambis, A. K.; Bobylev, V. V.; Bajkova, A. T. +3 more
We applied the currently most comprehensive version of the statistical-parallax technique to derive the kinematical parameters of the maser sample with 136 sources. Our kinematic model comprises the overall rotation of the Galactic disk and the spiral density-wave effects, and the variation of radial velocity dispersion with Galactocentric distanc…
Fractal dust constrains the collisional history of comets
Blum, J.; Fulle, M.
The fractal dust particles observed by Rosetta cannot form in the physical conditions observed today in comet 67P/Churyumov-Gerasimenko (67P hereinafter), being instead consistent with models of the pristine dust aggregates coagulated in the solar nebula. Since bouncing collisions in the protoplanetary disc restructure fractals into compact aggreg…
Evolution of N/O abundance ratios and ionization parameters from z ∼ 0 to 2 investigated by the direct temperature method*†
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +3 more
We present N/O abundance ratios, ionization parameters qion, and oxygen abundances O/H for a total of 41 galaxies (11 individual galaxies and a 30-galaxy stack) including Lyα emitters and Lyman break galaxies at z ∼ 2, and investigate galaxy evolution from z ∼ 0 to 2 in conjunction with 208529 local galaxies from the Sloan Digital Sky S…
Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality
Bailin, Jeremy; Rothberg, Barry; Harris, William E. +4 more
We present new deep photometry of the rich globular cluster (GC) systems around the Brightest Cluster Galaxies UGC 9799 (Abell 2052) and UGC 10143 (Abell 2147), obtained with the Hubble Space Telescope (HST) ACS and WFC3 cameras. For comparison, we also present new reductions of similar HST/ACS data for the Coma supergiants NGC 4874 and 4889. All …
The Grism Lens-amplified Survey from Space (GLASS). X. Sub-kiloparsec Resolution Gas-phase Metallicity Maps at Cosmic Noon behind the Hubble Frontier Fields Cluster MACS1149.6+2223
Fontana, Adriano; Schmidt, Kasper B.; Treu, Tommaso +17 more
We combine deep Hubble Space Telescope grism spectroscopy with a new Bayesian method to derive maps of gas-phase metallicity for 10 star-forming galaxies at high redshift (1.2≲ z≲ 2.3). Exploiting lensing magnification by the foreground cluster MACS1149.6+2223, we reach sub-kiloparsec spatial resolution and push the limit of stellar mass associate…