| Full text | |
| Author(s): |
Limberg, Guilherme
;
Queiroz, Anna B. A.
;
Perottoni, Helio D.
;
Rossi, Silvia
;
Amarante, Joao A. S.
;
Santucci, Rafael M.
;
Chiappini, Cristina
;
Perez-Villegas, Angeles
;
Lee, Young Sun
Total Authors: 9
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 946, n. 2, p. 15-pg., 2023-04-01. |
| Abstract | |
In this work, we study the phase-space and chemical properties of the Sagittarius (Sgr) stream, the tidal tails produced by the ongoing destruction of the Sgr dwarf spheroidal (dSph) galaxy, focusing on its very metal-poor (VMP; [Fe/H] < -2) content. We combine spectroscopic and astrometric information from SEGUE and Gaia EDR3, respectively, with data products from a new large-scale run of the StarHorse spectrophotometric code. Our selection criteria yield similar to 1600 stream members, including >200 VMP stars. We find the leading arm (b > 0 degrees) of the Sgr stream to be more metal-poor, by similar to 0.2 dex, than the trailing one (b < 0 degrees). With a subsample of turnoff and subgiant stars, we estimate this substructure's stellar population to be similar to 1 Gyr older than the thick disk's. With the aid of an N-body model of the Sgr system, we verify that simulated particles stripped earlier (>2 Gyr ago) have present-day phase-space properties similar to lower metallicity stream stars. Conversely, those stripped more recently (<2 Gyr) are preferentially akin to metal-rich ([Fe/H] > -1) members of the stream. Such correlation between kinematics and chemistry can be explained by the existence of a dynamically hotter, less centrally concentrated, and more metal-poor population in Sgr dSph prior to its disruption, implying that this galaxy was able to develop a metallicity gradient before its accretion. Finally, we identified several carbon-enhanced metal-poor ([C/Fe] > +0.7 and [Fe/H] <= -1.5) stars in the Sgr stream, which might be in tension with current observations of its remaining core where such objects are not found. (AU) | |
| FAPESP's process: | 22/04079-0 - Characterizing ultra-faint dwarf galaxies with S-PLUS survey |
| Grantee: | Hélio Dotto Perottoni |
| Support Opportunities: | Scholarships abroad - Research Internship - Post-doctor |
| FAPESP's process: | 18/21250-9 - Identification of bright ultra-metal-poor stars from Multi-Band photometry and spectroscopic follow-up |
| Grantee: | Hélio Dotto Perottoni |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 15/50374-0 - Mosaic: the multi-object spectrograph for the ESO Extremely Large Telescope |
| Grantee: | Silvia Cristina Fernandes Rossi |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 14/18100-4 - Stellar populations in the Milky Way: bulge, halo, disk and star forming regions; instrumentation for high resolution spectroscopy |
| Grantee: | Beatriz Leonor Silveira Barbuy |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 21/10429-0 - The chemodynamical structure of the ancient galactic halo |
| Grantee: | Guilherme Limberg |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 22/07301-5 - Chemical-abundance patterns of disrupted dwarf galaxies |
| Grantee: | Guilherme Limberg |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate (Direct) |