SMHASH: anatomy of the Orphan Stream using RR Lyrae stars. Issue 1 (5th June 2018)
- Record Type:
- Journal Article
- Title:
- SMHASH: anatomy of the Orphan Stream using RR Lyrae stars. Issue 1 (5th June 2018)
- Main Title:
- SMHASH: anatomy of the Orphan Stream using RR Lyrae stars
- Authors:
- Hendel, David
Scowcroft, Victoria
Johnston, Kathryn V
Fardal, Mark A
van der Marel, Roeland P
Sohn, Sangmo T
Price-Whelan, Adrian M
Beaton, Rachael L
Besla, Gurtina
Bono, Giuseppe
Cioni, Maria-Rosa L
Clementini, Giselle
Cohen, Judith G
Fabrizio, Michele
Freedman, Wendy L
Garofalo, Alessia
Grillmair, Carl J
Kallivayalil, Nitya
Kollmeier, Juna A
Law, David R
Madore, Barry F
Majewski, Steven R
Marengo, Massimo
Monson, Andrew J
Neeley, Jillian R
Nidever, David L
Pietrzyński, Grzegorz
Seibert, Mark
Sesar, Branimir
Smith, Horace A
Soszyński, Igor
Udalski, Andrzej
… (more) - Abstract:
- ABSTRACT: Stellar tidal streams provide an opportunity to study the motion and structure of the disrupting galaxy as well as the gravitational potential of its host. Streams around the Milky Way are especially promising as phase space positions of individual stars will be measured by ongoing or upcoming surveys. Nevertheless, it remains a challenge to accurately assess distances to stars farther than 10 kpc from the Sun, where we have the poorest knowledge of the Galaxy's mass distribution. To address this, we present observations of 32 candidate RR Lyrae stars in the Orphan tidal stream taken as part of the Spitzer Merger History and Shape of the Galactic Halo (SMHASH) program. The extremely tight correlation between the periods, luminosities, and metallicities of RR Lyrae variable stars in the Spitzer IRAC $\mathrm{3.6 \, \mu m}$ band allows the determination of precise distances to individual stars; the median statistical relative distance uncertainty to each RR Lyrae star is 2.5 per cent. By fitting orbits in an example potential, we obtain an upper limit on the mass of the Milky Way interior to 60 kpc of $\mathrm{5.6_{-1.1}^{+1.2}\times 10^{11}\ M_\odot}$, bringing estimates based on the Orphan Stream in line with those using other tracers. The SMHASH data also resolve the stream in line-of-sight depth, allowing a new perspective on the internal structure of the disrupted dwarf galaxy. Comparing with N –body models, we find that the progenitor had an initial dark haloABSTRACT: Stellar tidal streams provide an opportunity to study the motion and structure of the disrupting galaxy as well as the gravitational potential of its host. Streams around the Milky Way are especially promising as phase space positions of individual stars will be measured by ongoing or upcoming surveys. Nevertheless, it remains a challenge to accurately assess distances to stars farther than 10 kpc from the Sun, where we have the poorest knowledge of the Galaxy's mass distribution. To address this, we present observations of 32 candidate RR Lyrae stars in the Orphan tidal stream taken as part of the Spitzer Merger History and Shape of the Galactic Halo (SMHASH) program. The extremely tight correlation between the periods, luminosities, and metallicities of RR Lyrae variable stars in the Spitzer IRAC $\mathrm{3.6 \, \mu m}$ band allows the determination of precise distances to individual stars; the median statistical relative distance uncertainty to each RR Lyrae star is 2.5 per cent. By fitting orbits in an example potential, we obtain an upper limit on the mass of the Milky Way interior to 60 kpc of $\mathrm{5.6_{-1.1}^{+1.2}\times 10^{11}\ M_\odot}$, bringing estimates based on the Orphan Stream in line with those using other tracers. The SMHASH data also resolve the stream in line-of-sight depth, allowing a new perspective on the internal structure of the disrupted dwarf galaxy. Comparing with N –body models, we find that the progenitor had an initial dark halo mass of approximately 3.2 × 10 9 M⊙, placing the Orphan Stream's progenitor amongst the classical dwarf spheroidals. … (more)
- Is Part Of:
- Monthly notices of the Royal Astronomical Society. Volume 479:Issue 1(2018)
- Journal:
- Monthly notices of the Royal Astronomical Society
- Issue:
- Volume 479:Issue 1(2018)
- Issue Display:
- Volume 479, Issue 1 (2018)
- Year:
- 2018
- Volume:
- 479
- Issue:
- 1
- Issue Sort Value:
- 2018-0479-0001-0000
- Page Start:
- 570
- Page End:
- 587
- Publication Date:
- 2018-06-05
- Subjects:
- stars: variables: RR Lyrae -- Galaxy: halo -- Galaxy: kinematics and dynamics -- Galaxy: structure
Astronomy -- Periodicals
Periodicals
520.5 - Journal URLs:
- http://mnras.oxfordjournals.org/ ↗
http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2966 ↗
http://www.blackwell-synergy.com/issuelist.asp?journal=mnr ↗
http://www.blackwell-synergy.com/loi/mnr ↗
http://ukcatalogue.oup.com/ ↗ - DOI:
- 10.1093/mnras/sty1455 ↗
- Languages:
- English
- ISSNs:
- 0035-8711
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 5943.000000
British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 12522.xml