scholarly journals A Pan-STARRS1 Search for Substellar Young Moving Group Members

2015 ◽  
Vol 10 (S314) ◽  
pp. 54-57
Author(s):  
Kimberly M. Aller ◽  
Michael C. Liu ◽  
Eugene A. Magnier
Keyword(s):  
Large Scale ◽  
Spectral Characteristics ◽  
Mass Function ◽  
Initial Mass Function ◽  
Valuable Insight ◽  
Near Ir ◽  
Group Members ◽  
Low Mass ◽  
Moving Groups ◽  
Ir Photometry

AbstractYoung moving groups (YMGs) are coeval, comoving groups of stars which have migrated from their birthsites after formation. In the substellar regime, YMG members are key benchmarks to empirically define brown dwarf evolution with age and to study the lowest mass end of the initial mass function. We have combined Pan-STARRS1 (PS1) proper motions with optical+IR photometry from PS1, 2MASS and WISE to perform a large-scale (≈30,000 deg2) systematic search for substellar members down to ≈10 MJup. We have obtained near-IR spectroscopy of a large sample of ultracool candidate YMG members to assess their youth via gravity-sensitive absorption features. We have identified several new intermediate-gravity candidate members of the AB Dor Moving Group, potentially greatly expanding the substellar membership. These new candidate members bridge the gap between the known low-mass stellar and planetary-mass members and yield valuable insight into the spectral characteristics of young brown dwarfs.

Low‐Mass Star Formation and the Initial Mass Function in IC 348

1998 ◽  
Vol 508 (1) ◽  
pp. 347-369 ◽  
Author(s):  
K. L. Luhman ◽  
G. H. Rieke ◽  
C. J. Lada ◽  
E. A. Lada
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Mass Star ◽  
Low Mass

scholarly journals Very Low-Luminosity Objects in Star-Forming Regions

1998 ◽  
Vol 11 (1) ◽  
pp. 423-424
Author(s):  
Motohide Tamura ◽  
Yoichi Itoh ◽  
Yumiko Oasa ◽  
Alan Tokunaga ◽  
Koji Sugitani
Keyword(s):  
Brown Dwarfs ◽  
Mass Function ◽  
T Tauri Stars ◽  
Initial Mass Function ◽  
Formation Mechanisms ◽  
Star Forming ◽  
Star Forming Regions ◽  
T Tauri ◽  
Low Mass ◽  
Stellar Sources

Abstract In order to tackle the problems of low-mass end of the initial mass function (IMF) in star-forming regions and the formation mechanisms of brown dwarfs, we have conducted deep infrared surveys of nearby molecular clouds. We have found a significant population of very low-luminosity sources with IR excesses in the Taurus cloud and the Chamaeleon cloud core regions whose extinction corrected J magnitudes are 3 to 8 mag fainter than those of typical T Tauri stars in the same cloud. Some of them are associated with even fainter companions. Follow-up IR spectroscopy has confirmed for the selected sources that their photospheric temperature is around 2000 to 3000 K. Thus, these very low-luminosity young stellar sources are most likely very low-mass T Tauri stars, and some of them might even be young brown dwarfs.

scholarly journals Processes controlling the initial mass function: interstellar turbulence and magnetic fields

1991 ◽  
Vol 147 ◽  
pp. 407-408
Author(s):  
R. C. Fleck
Keyword(s):  
Magnetic Fields ◽  
Mass Function ◽  
Diffusion Time ◽  
Interstellar Cloud ◽  
Initial Mass Function ◽  
Mass Scaling ◽  
Interstellar Turbulence ◽  
Time Scaling ◽  
Turbulent Pressure ◽  
Low Mass

The observed flattening of the initial stellar mass function at low mass can be accounted for in terms of the different interstellar cloud size-mass scaling and different ambipolar diffusion time scaling for small, thermally-supported clouds and larger clouds supported primarily by turbulent pressure.

scholarly journals The young star cluster NGC 2362: low-mass population and initial mass function from a Chandra X-ray observation

2006 ◽  
Vol 460 (1) ◽  
pp. 133-144 ◽  
Author(s):  
F. Damiani ◽  
G. Micela ◽  
S. Sciortino ◽  
N. Huélamo ◽  
A. Moitinho ◽  
...  
Keyword(s):  
Mass Function ◽  
Young Star ◽  
Star Cluster ◽  
Initial Mass Function ◽  
Initial Mass ◽  
X Ray ◽  
Low Mass

Clues to Substellar Formation: Rotation and the Low-Mass End of the Initial Mass Function

2004 ◽  
pp. 499-505
Author(s):  
María Rosa Zapatero Osorio ◽  
José Caballero ◽  
Eduardo L. Martín ◽  
Víctor J. S. Béjar ◽  
Rafael Rebolo
Keyword(s):  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Low Mass

scholarly journals The Stellar Initial Mass Function in Starburst Galaxies

1999 ◽  
Vol 186 ◽  
pp. 243-250
Author(s):  
Claus Leitherer
Keyword(s):  
Massive Stars ◽  
Mass Function ◽  
Starburst Galaxies ◽  
Initial Mass Function ◽  
Initial Mass ◽  
H Ii Regions ◽  
Environmental Properties ◽  
Stellar Initial Mass Function ◽  
Low Mass ◽  
Star Formation Histories

Starburst galaxies are currently forming massive stars at prodigious rates. I discuss the star-formation histories and the shape of the initial mass function, with particular emphasis on the high- and on the low-mass end. The classical Salpeter IMF is consistent with constraints from observations of the most massive stars, irrespective of environmental properties. The situation at the low-mass end is less clear: direct star counts in nearby giant H II regions show stars down to ~1 M⊙, whereas dynamical arguments in some starburst galaxies suggest a deficit of such stars.

scholarly journals Stellar populations in the highest redshift galaxies

2015 ◽  
Vol 11 (A29B) ◽  
pp. 197-198
Author(s):  
Andrew J. Bunker
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Star Forming ◽  
Near Ir ◽  
James Webb Space Telescope ◽  
Large Telescopes ◽  
The Universe

AbstractI discuss stellar populations in galaxies at high redshift (z > 6), in particular the blue rest-frame UV colours which have been detected in recent years through near-IR imaging with HST. These spectral slopes of β < −2 are much more blue than star-forming galaxies at lower redshift, and may suggest less dust obscuration, lower metallicity or perhaps a different initial mass function. I describe current work on the luminosity function of high redshift star- forming galaxies, the evolution of the fraction of strong Lyman-α emitters in this population, and the contribution of the ionizing photon budget from such galaxies towards the reionization of the Universe. I also describe constraints placed by Spitzer/IRAC on stellar populations in galaxies within the first billion years, and look towards future developments in spectroscopy with Extremely Large Telescopes and the James Webb Space Telescope, including the JWST/NIRSpec GTO programme on galaxy evolution at high redshift.

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