Search Publications
Gaia luminosities of pulsating A-F stars in the Kepler field
Balona, L. A.
All stars in the Kepler field brighter than 12.5 mag have been classified according to variability type. A catalogue of δ Scuti and γ Doradus stars is presented. The problem of low frequencies in δ Sct stars, which occurs in over 98 percent of these stars, is discussed. Gaia DR2 parallaxes were used to obtain precise luminosities, enabling the ins…
hCOSMOS: A Dense Spectroscopic Survey of r ≤ 21.3 Galaxies in the COSMOS field
Hwang, Ho Seong; Geller, Margaret J.; Damjanov, Ivana +2 more
We describe the hCOSMOS redshift survey of the COSMOS field conducted with the Hectospec spectrograph on the MMT. In the central 1 deg2, the hCOS20.6 subset of the survey is > 90 % complete to a limiting magnitude r = 20.6. The hCOSMOS survey includes 1701 new redshifts in the COSMOS field. We also use the total of 4362 new and remea…
Revised historical solar irradiance forcing
Egorova, T.; Schmutz, W.; Rozanov, E. +5 more
Context. There is no consensus on the amplitude of historical solar forcing. The estimated magnitude of the total solar irradiance (TSI) difference between the Maunder minimum and the present time ranges from 0.1 to 6 W m-2 making the simulation of the past and future climate uncertain. One reason for this disagreement is the applied ev…
Evidence for feedback and stellar-dynamically regulated bursty star cluster formation: the case of the Orion Nebula Cluster
Kroupa, Pavel; Beccari, Giacomo; Jeřábková, Tereza +2 more
A scenario for the formation of multiple co-eval populations separated in age by about 1 Myr in very young clusters (VYCs, ages less than 10 Myr) and with masses in the range 600-20 000 M⊙ is outlined. It rests upon a converging inflow of molecular gas building up a first population of pre-main sequence stars. The associated just-formed…
ETHOS - an effective theory of structure formation: predictions for the high-redshift Universe - abundance of galaxies and reionization
Vogelsberger, Mark; Pillepich, Annalisa; Lovell, Mark R. +6 more
We contrast predictions for the high-redshift galaxy population and reionization history between cold dark matter (CDM) and an alternative self-interacting dark matter model based on the recently developed ETHOS framework that alleviates the small-scale CDM challenges within the Local Group. We perform the highest resolution hydrodynamical cosmolo…
An L Band Spectrum of the Coldest Brown Dwarf
Fortney, Jonathan J.; Freedman, Richard S.; Faherty, Jacqueline K. +10 more
The coldest brown dwarf, WISE 0855, is the closest known planetary-mass, free-floating object and has a temperature nearly as cold as the solar system gas giants. Like Jupiter, it is predicted to have an atmosphere rich in methane, water, and ammonia, with clouds of volatile ices. WISE 0855 is faint at near-infrared wavelengths and emits almost al…
Super-strong Magnetic Field in Sunspots
Okamoto, Takenori J.; Sakurai, Takashi
Sunspots are the most notable structure on the solar surface with strong magnetic fields. The field is generally strongest in a dark area (umbra), but sometimes stronger fields are found in non-dark regions, such as a penumbra and a light bridge. The formation mechanism of such strong fields outside umbrae is still puzzling. Here we report clear e…
Molecular gas content in obscured AGN at z > 1
Daddi, E.; Sargent, M. T.; Vignali, C. +11 more
Aims: The standard active galactic nuclei (AGN)-galaxy co-evolutionary scenario predicts a phase of deeply "buried" supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous quasar (QSO) is revealed (called the SB-QSO evolutionary …
Search for star cluster age gradients across spiral arms of three LEGUS disc galaxies
Cignoni, M.; Tosi, M.; Sabbi, E. +20 more
One of the main theories for explaining the formation of spiral arms in galaxies is the stationary density wave theory. This theory predicts the existence of an age gradient across the arms. We use the stellar cluster catalogues of the galaxies NGC 1566, M51a, and NGC 628 from the Legacy ExtraGalactic UV Survey (LEGUS) program. In order to test fo…
catsHTM: A Tool for Fast Accessing and Cross-matching Large Astronomical Catalogs
Soumagnac, Maayane T.; Ofek, Eran O.
Fast access to large catalogs is required for some astronomical applications. Here we introduce the catsHTM tool, consisting of several large catalogs reformatted into HDF5-based file format, which can be downloaded and used locally. To allow fast access, the catalogs are partitioned into hierarchical triangular meshes and stored in HDF5 files. Se…