Abstract
Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of identifying stars in the field, especially low-mass stars with stellar types M0 and later. The PEARS fields lay within the larger GOODS fields, and we used new, deeper images to further refine the selection of stars in the PEARS field, down to a magnitude of z850 = 25 using a newly developed stellarity parameter. The total number of stars with reliable spectroscopic and morphological identification was 95 and 108 in the north and south fields, respectively. The sample of spectroscopically identified stars allows constraints to be set on the thickness of the Galactic thin disk as well as contributions from a thick disk and a halo component. We derive a thin disk scale height, as traced by the population of M4-M9 dwarfs along two independent lines of sight, of hthin = 370+60 -65 pc. When including the more massive M0-M4 dwarf population, we derive hthin= 300 ± 70 pc. In both cases, we observe that we must include a combination of thick and halo components in our models in order to account for the observed numbers of faint dwarfs. The required thick disk scale height is typically hthick = 1000 pc and the acceptable relative stellar densities of the thin disk to thick disk and the thin disk to halo components are in the range of 0.00025 < fhalo < 0.0005 and 0.05 < fhalo < 0.08 and are somewhat dependent on whether the more massive M0-M4 dwarfs are included in our sample.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1591-1603 |
| Number of pages | 13 |
| Journal | Astrophysical Journal |
| Volume | 695 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 20 2009 |
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Keywords
- Color figures
- Disk
- Galaxy
- Galaxy
- Galaxy
- Galaxy
- Halo
- Late-Type online-only material
- Stars
- Stellar content
- Structure
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
Spectrophotometrically identified stars in the pears-n and pears-s fields. / Pirzkal, N.; Burgasser, A. J.; Malhotra, S.; Holwerda, B. W.; Sahu, K. C.; Rhoads, J. E.; Xu, C.; Bochanski, J. J.; Walsh, J. R.; Windhorst, Rogier; Hathi, N. P.; Cohen, S. H.
In: Astrophysical Journal, Vol. 695, No. 2, 20.04.2009, p. 1591-1603.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Spectrophotometrically identified stars in the pears-n and pears-s fields
AU - Pirzkal, N.
AU - Burgasser, A. J.
AU - Malhotra, S.
AU - Holwerda, B. W.
AU - Sahu, K. C.
AU - Rhoads, J. E.
AU - Xu, C.
AU - Bochanski, J. J.
AU - Walsh, J. R.
AU - Windhorst, Rogier
AU - Hathi, N. P.
AU - Cohen, S. H.
PY - 2009/4/20
Y1 - 2009/4/20
N2 - Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of identifying stars in the field, especially low-mass stars with stellar types M0 and later. The PEARS fields lay within the larger GOODS fields, and we used new, deeper images to further refine the selection of stars in the PEARS field, down to a magnitude of z850 = 25 using a newly developed stellarity parameter. The total number of stars with reliable spectroscopic and morphological identification was 95 and 108 in the north and south fields, respectively. The sample of spectroscopically identified stars allows constraints to be set on the thickness of the Galactic thin disk as well as contributions from a thick disk and a halo component. We derive a thin disk scale height, as traced by the population of M4-M9 dwarfs along two independent lines of sight, of hthin = 370+60 -65 pc. When including the more massive M0-M4 dwarf population, we derive hthin= 300 ± 70 pc. In both cases, we observe that we must include a combination of thick and halo components in our models in order to account for the observed numbers of faint dwarfs. The required thick disk scale height is typically hthick = 1000 pc and the acceptable relative stellar densities of the thin disk to thick disk and the thin disk to halo components are in the range of 0.00025 < fhalo < 0.0005 and 0.05 < fhalo < 0.08 and are somewhat dependent on whether the more massive M0-M4 dwarfs are included in our sample.
AB - Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of identifying stars in the field, especially low-mass stars with stellar types M0 and later. The PEARS fields lay within the larger GOODS fields, and we used new, deeper images to further refine the selection of stars in the PEARS field, down to a magnitude of z850 = 25 using a newly developed stellarity parameter. The total number of stars with reliable spectroscopic and morphological identification was 95 and 108 in the north and south fields, respectively. The sample of spectroscopically identified stars allows constraints to be set on the thickness of the Galactic thin disk as well as contributions from a thick disk and a halo component. We derive a thin disk scale height, as traced by the population of M4-M9 dwarfs along two independent lines of sight, of hthin = 370+60 -65 pc. When including the more massive M0-M4 dwarf population, we derive hthin= 300 ± 70 pc. In both cases, we observe that we must include a combination of thick and halo components in our models in order to account for the observed numbers of faint dwarfs. The required thick disk scale height is typically hthick = 1000 pc and the acceptable relative stellar densities of the thin disk to thick disk and the thin disk to halo components are in the range of 0.00025 < fhalo < 0.0005 and 0.05 < fhalo < 0.08 and are somewhat dependent on whether the more massive M0-M4 dwarfs are included in our sample.
KW - Color figures
KW - Disk
KW - Galaxy
KW - Galaxy
KW - Galaxy
KW - Galaxy
KW - Halo
KW - Late-Type online-only material
KW - Stars
KW - Stellar content
KW - Structure
UR - http://www.scopus.com/inward/record.url?scp=75649134751&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=75649134751&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/695/2/1591
DO - 10.1088/0004-637X/695/2/1591
M3 - Article
AN - SCOPUS:75649134751
VL - 695
SP - 1591
EP - 1603
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -