Search Publications
The SOPHIE search for northern extrasolar planets. XIV. A temperate (Teq 300 K) super-earth around the nearby star Gliese 411
Bouchy, F.; Deleuil, M.; Moutou, C. +33 more
Periodic radial velocity variations in the nearby M-dwarf star Gl 411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08 days, but favour the former slightly. The velocity variation has an amplitude of 1.6 m s-1, making th…
The chemical composition of HIP 34407/HIP 34426 and other twin-star comoving pairs
Lambert, D. L.; Endl, M.; Meléndez, J. +4 more
We conducted a high-precision elemental abundance analysis of the twin-star comoving pair HIP 34407/HIP 34426. With mean error of 0.013 dex in the differential abundances (Δ[X/H]), a significant difference was found: HIP 34407 is more metal rich than HIP 34426. The elemental abundance differences correlate strongly with condensation temperature, w…
A Census of Early-phase High-mass Star Formation in the Central Molecular Zone
Ott, Jürgen; Lu, Xing; Henshaw, Jonathan D. +13 more
We present new observations of the C-band continuum emission and masers to assess high-mass (>8 {M}⊙ ) star formation at early evolutionary phases in the inner 200 pc of the Central Molecular Zone (CMZ) of the Galaxy. The continuum observation is complete to free-free emission from stars above 10-11 {M}⊙ in 91% of the cov…
The diverse galaxy counts in the environment of high-redshift massive black holes in Horizon-AGN
Somerville, Rachel S.; Volonteri, Marta; Habouzit, Mélanie +4 more
High-redshift quasars are believed to reside in highly biased regions of the Universe, where black hole growth is sustained by an enhanced number of mergers and by being at the intersection of filaments bringing fresh gas. This assumption should be supported by an enhancement of the number counts of galaxies in the field of view of quasars. While …
The power spectrum of the Lyman-α Forest at z < 0.5
Hennawi, Joseph F.; Tripp, Todd M.; Prochaska, J. Xavier +7 more
We present new measurements of the flux power-spectrum P(k) of the z < 0.5 H I Lyman-α Forest spanning scales k ∼ 0.001-0.1 s km^{-1}. These results were derived from 65 far-ultraviolet quasar spectra (resolution R ∼ 18 000) observed with the Cosmic Origin Spectrograph (COS) on board the Hubble Space Telescope. The analysis required careful mas…
The nuclear environment of the NLS1 Mrk 335: Obscuration of the X-ray line emission by a variable outflow
Harrison, F. A.; Schartel, N.; Santos-Lleó, M. +12 more
We present XMM-Newton, NuSTAR, Swift, and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely low continuum flux reveals a host of soft X-ray emission lines from photoionized gas. The simultaneous UV flux…
The structure of the Mg II broad line emitting region in Type 1 AGNs
Popović, Luka Č.; Kovačević-Dojčinović, Jelena; Marčeta-Mandić, Sladjana
We investigate the structure of the Mg II broad line emission region in a sample of 284 Type 1 active galactic nuclei (AGNs), through comparing the kinematical parameters of the broad Mg II and broad Hβ lines. We found that the Mg II emitting region has more complex kinematics than the Hβ one. It seems that the Mg II broad line originates from two…
UVIT Open Cluster Study. II. Detection of Extremely Low Mass White Dwarfs and Post-Mass Transfer Binaries in M67
Jadhav, Vikrant V.; Subramaniam, Annapurni; Sindhu, N.
A detailed study of the UV-bright stars in the old open star cluster M67 is presented based on the far-UV observations using the Ultra Violet Imaging Telescope (UVIT) on ASTROSAT. The UV and UV-optical color-magnitude diagrams (CMDs), along with overlaid isochrones, are presented for the member stars, which include blue straggler stars (BSSs), tri…
Benchmark ages for the Gaia benchmark stars
Feltzing, Sofia; Lindegren, Lennart; Sahlholdt, Christian L. +1 more
In the era of large-scale surveys of stars in the Milky Way, stellar ages are crucial for studying the evolution of the Galaxy. But determining ages of field stars is notoriously difficult; therefore, we attempt to determine benchmark ages for the extensively studied Gaia benchmark stars which can be used for validation purposes. By searching the …
Chemical Abundances along the 1G Sequence of the Chromosome Maps: The Globular Cluster NGC 3201
Milone, A. P.; Cordoni, G.; Marino, A. F. +10 more
The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the “chromosome map” (ChM) diagnostic tool that maximizes the separation between stars with different chemical compositions. One of the most challenging features revealed by ChM analysis is the apparent in…