Battaglia, G. and Irwin, M. and Tolstoy, E. and Hill, V. and Helmi, A. and Letarte, B. and Jablonka, P. (2008) Analysis and calibration of Ca II triplet spectroscopy of red giant branch stars from VLT/FLAMES observations. Monthly Notices of the Royal Astronomical Society, 383 (1). pp. 183-199. ISSN 0035-8711. doi:10.1111/j.1365-2966.2007.12532.x. https://resolver.caltech.edu/CaltechAUTHORS:20091016-092634520
![[img]](https://authors.library.caltech.edu/style/images/fileicons/application_pdf.png)
|
PDF
- Published Version
See Usage Policy. 661kB | |
|
PDF (Table 3 (sm001.pdf))
- Supplemental Material
See Usage Policy. 58kB | |
|
PDF (Table 4 (sm002.pdf))
- Supplemental Material
See Usage Policy. 65kB | |
|
PDF (Table 3 (sm003.pdf))
- Supplemental Material
See Usage Policy. 58kB | |
|
PDF (Table 4 (sm004.pdf))
- Supplemental Material
See Usage Policy. 65kB |
Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20091016-092634520
Abstract
We demonstrate that low-resolution Ca ii triplet (CaT) spectroscopic estimates of the overall metallicity ([Fe/H]) of individual red giant branch (RGB) stars in two nearby dwarf spheroidal galaxies (dSphs) agree to ±0.1–0.2 dex with detailed high-resolution spectroscopic determinations for the same stars over the range −2.5 < [Fe/H] < −0.5 . For this study, we used a sample of 129 stars observed in low- and high-resolution modes with VLT/FLAMES in the Sculptor and Fornax dSphs. We also present the data-reduction steps we used in our low-resolution analysis and show that the typical accuracy of our velocity and CaT [Fe/H] measurement is ~2 km s^(−1) and 0.1 dex, respectively. We conclude that CaT–[Fe/H] relations calibrated on globular clusters can be applied with confidence to RGB stars in composite stellar populations over the range −2.5 < [Fe/H] < −0.5 .
| Item Type: | Article | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Related URLs: |
| |||||||||
| ORCID: |
| |||||||||
| Additional Information: | © 2007 The Authors. Journal compilation © 2007 RAS. Accepted 2007 September 28. Received 2007 September 25; in original form 2007 April 20. We acknowledge F. Pont for kindly providing the EWs of the individual CaT lines in electronic form. We thank A. Cole for useful discussions. AH acknowledges support from NWO and NOVA. SUPPLEMENTARY MATERIAL: The following supplementary material is available for this article: Table 3. This table lists the relevant data for the stars in the globular clusters NGC 104, NGC 3201, NGC 4590 and NGC 5904 observed with VLT/FLAMES at LR, and that we used in the analysis of the CaT–[Fe/H] calibration. For the CaT analysis, we select only those stars whose colour and magnitude are consistent with what is expected for RGB stars, and that have V − VHB < 0, S/N > 10 per Åerror in velocity <5 km s−1 and velocities consistent with membership to the cluster (we assign membership to those stars within 3σ of the systemic velocity, see Table 1). The columns indicates: (1): the globular cluster name; (2): the star ID; (3) and (4): star coordinates (right ascension in hours and declination in degrees); (5) and (6): V magnitude and its error; (7) and (8): heliocentric velocity and its error; (9) and (10): summed CaT EW (EW2 + EW3) and its error; (11) and (12): [Fe/H] value and its error, derived from the LR observations applying equation (16). The photometry and astrometry are from Stetson (2000). Table 4. This table lists the relevant data for the stars observed with VLT/FLAMES at both LR and HR in the Sculptor and Fornax dSphs, and used in the analysis of the CaT–[Fe/H] calibration. The columns indicates: (1): the galaxy name; (2): the star ID; (3) and (4): star coordinates (right ascension in hours and declination in degrees); (5) and (6): V magnitude and its error; (7) and (8): heliocentric velocity and its error; (9) and (10): summed CaT EW (EW2 + EW3) and its error; (11) and (12): [Fe/H] value derived from the LR observations applying equation (16) and its error; (13) and (14): HR [Fe/H] value and error; (15) and (16): [Ca/Fe] and its error, from the HR observations. The photometry and astrometry are from our ESO/WFI observations (Tolstoy et al. 2004; Battaglia et al. 2006). Those stars with [Ca/Fe]= −9.99 had too low S/N to allow for a determination of the HR [Ca/H]. | |||||||||
| Funders: |
| |||||||||
| Subject Keywords: | techniques : spectroscopic; stars : abundances; galaxies : dwarf; galaxies : star clusters | |||||||||
| Issue or Number: | 1 | |||||||||
| DOI: | 10.1111/j.1365-2966.2007.12532.x | |||||||||
| Record Number: | CaltechAUTHORS:20091016-092634520 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20091016-092634520 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 16359 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Tony Diaz | |||||||||
| Deposited On: | 26 Oct 2009 19:52 | |||||||||
| Last Modified: | 08 Nov 2021 23:26 |
Repository Staff Only: item control page
