Results 1 to 10 of about 40 (37)

New Cold Subdwarf Discoveries from Backyard Worlds and a Metallicity Classification System for T Subdwarfs

The Astrophysical Journal
We report the results of a spectroscopic survey of candidate T subdwarfs identified by the Backyard Worlds: Planet 9 program. Near-infrared spectra of 31 sources with red J  − W2 colors and large J -band reduced proper motions show varying signatures of ...
Adam J. Burgasser, Adam C. Schneider, Aaron M. Meisner, Dan Caselden, Chih-Chun Hsu, Roman Gerasimov, Christian Aganze, Emma Softich, Preethi Karpoor, Christopher A. Theissen, Hunter Brooks, Thomas P. Bickle, Jonathan Gagné, Ètienne Artigau, Michaël Marsset, Austin Rothermich, Jacqueline K. Faherty, J. Davy Kirkpatrick, Marc J. Kuchner, Nikolaj Stevnbak Andersen, Paul Beaulieu, Guillaume Colin, Jean Marc Gantier, Leopold Gramaize, Les Hamlet, Ken Hinckley, Martin Kabatnik, Frank Kiwy, David W. Martin, Diego H. Massat, William Pendrill, Arttu Sainio, Jörg Schümann, Melina Thévenot, Jim Walla, Zbigniew Wędracki, The Backyard Worlds: Planet 9 Collaboration   +36 more
doaj   +4 more sources

Discovery of CWISE J052306.42−015355.4, an Extreme T Subdwarf Candidate [PDF]

The Astronomical Journal, 2022
Abstract We present the discovery of CWISE J052306.42−015355.4, which was found as a faint, significant proper-motion object (0.″52 ± 0.″08 yr−1) using machine-learning tools on the unWISE re-processing of time series images from the Wide-field Infrared Survey Explorer.
Brooks, Hunter, Kirkpatrick, J. Davy, Caselden, Dan, Schneider, Adam C., Meisner, Aaron M., Faherty, Jacqueline K., Casewell, S. L., Kuchner, Marc J., Worlds, The Backyard, Collaboration, Planet 9   +9 more
openaire   +6 more sources

WISEA J041451.67–585456.7 and WISEA J181006.18–101000.5: The First Extreme T-type Subdwarfs? [PDF]

The Astrophysical Journal, 2020
Abstract We present the discoveries of WISEA J041451.67−585456.7 and WISEA J181006.18−101000.5, two low-temperature (1200–1400 K), high proper motion T-type subdwarfs. Both objects were discovered via their high proper motion (>0.″5 yr−1); WISEA J181006.18−101000.5 as part of the NEOWISE proper motion survey and WISEA J041451.67 ...
Schneider, Adam C., Burgasser, Adam J., Gerasimov, Roman, Marocco, Federico, Gagne, Jonathan, Goodman, Sam, Beaulieu, Paul, Pendrill, William, Rothermich, Austin, Sainio, Arttu, Kuchner, Marc J., Caselden, Dan, Meisner, Aaron M., Faherty, Jacqueline K., Mamajek, Eric E., Hsu, Chih-Chun, Greco, Jennifer J., Cushing, Michael C., Kirkpatrick, J. Davy, Gagliuffi, Daniella Bardalez, Logsdon, Sarah E., Allers, Katelyn, Debes, John H., Worlds, The Backyard, Collaboration, Planet 9   +24 more
openaire   +3 more sources

Discovery of a Possible Early-T Thick-disk Subdwarf from the AllWISE2 Motion Survey* [PDF]

The Astronomical Journal, 2018
Abstract We have discovered a potential T0 ± 1 subdwarf from a search for sources in the AllWISE2 Motion Survey that do not have counterparts in surveys at shorter wavelengths. With a tangential velocity of ∼170 km s−1, this object—WISE J071121.36–573634.2—has kinematics that are consistent with the thick-disk population of the Milky Way.
Kendra Kellogg, J. Davy Kirkpatrick, Stanimir Metchev, Jonathan Gagné, Jacqueline K. Faherty   +4 more
openaire   +3 more sources

Exploring the Extremes: Characterizing a New Population of Old and Cold Brown Dwarfs

The Astronomical Journal, 2023
Mapping out the populations of thick disk and halo brown dwarfs is important for understanding the metallicity dependence of low-temperature atmospheres and the substellar mass function.
Aaron M. Meisner, S. K. Leggett, Sarah E. Logsdon, Adam C. Schneider, Pascal Tremblin, Mark Phillips   +5 more
doaj   +1 more source

unTimely: a Full-sky, Time-domain unWISE Catalog

The Astronomical Journal, 2023
We present the unTimely Catalog, a deep time-domain catalog of detections based on Wide-field Infrared Survey Explorer (WISE) and NEOWISE observations spanning the 2010 through 2020 time period. Detections are extracted from “time-resolved unWISE coadds,”
Aaron M. Meisner, Dan Caselden, Edward F. Schlafly, Frank Kiwy   +3 more
doaj   +1 more source

In Pursuit of the Least Luminous Galaxies

Advances in Astronomy, Volume 2010, Issue 1, 2010., 2010
The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter.
Beth Willman, Regina Schulte-Ladbeck
wiley   +1 more source

Ultracool Subdwarfs: Metal-poor Stars and Brown Dwarfs Extending into the Late-type M, L and T Dwarf Regimes

, 2004
Recent discoveries from red optical proper motion and wide-field near-infrared surveys have uncovered a new population of ultracool subdwarfs -- metal-poor stars and brown dwarfs extending into the late-type M, L and possibly T spectral classes. These objects are among the first low-mass stars and brown dwarfs formed in the Galaxy, and are valuable ...
Burgasser, Adam J., Kirkpatrick, J. Davy, Lepine, Sebastien   +2 more
openaire   +2 more sources

Se-ResNet+SVM Model: An Effective Method of Searching for Hot Subdwarfs from LAMOST

The Astrophysical Journal Supplement Series
This paper presents a robust neural network approach for identifying hot subdwarfs. Our method leveraged the Squeeze-and-Excitation Residual Network to extract abstract features, which were combined with experience features to create hybrid features ...
Zhongding Cheng, Xiaoming Kong, Tianmin Wu, Aina Zhang, Bowen Liu, Yude Bu, Zhenxin Lei, Yatao Zhang, Zhenping Yi, Meng Liu   +9 more
doaj   +1 more source

K _s -band Photometry of the Extreme T Subdwarf CWISE J221706.28−145437.6*

Research Notes of the AAS
Abstract We present deep K s -band imaging of the extreme T subdwarf CWISE J221706.28−145437.6. Using the new photometry, we construct its spectral energy distribution and find this object exhibits exceptionally strong collision-induced absorption in the H and K band.
Jerry J.-Y. 俊䶮 Zhang 章, Nicolas Lodieu, Eduardo L. Martín   +2 more
openaire   +2 more sources