GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
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2024
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| author | Valluri, Monica Fagrelius, Parker Koposov, Sergey. E. Li, Ting S. Gnedin, Oleg Y. Bell, Eric F. Carlberg, Raymond G. Cooper, Andrew P. Aguilar, Jessia N. Prieto, Carlos Allende Belokurov, Vasily Silva, Leandro Beraldo e Brooks, David Byström, Amanda Claybaugh, Todd Dawson, Kyle Dey, Arjun Doel, Peter Forero-Romero, Jaime E. Gaztañaga, Enrique Gontcho, Satya Gontcho A Honscheid, Klaus Kisner, T . Kremin, Anthony Lambert, A. Landriau, Martin Guillou, L. Le Levi, Michael E. de la Macorra, Axel Manera, Mark Martini, Paul Medina, Gustavo E. Meisner, Aaron Miquel, Ramon Moustakas, John Myer, Adam D. Najita, Joan Poppett, Claire Prada, Francisco Rezaie, Mehdi Rossi, Graziano Riley, Alex H. Sanchez, Eusebio Schlegel, David Schubnell, Michael Sprayberry, David Tarlé, Gregory Thomas, Guillaume Weaver, Benjamin A. Wechsler, Risa H. Zhou, Rongpu Zou, Hu |
| author_facet | Valluri, Monica Fagrelius, Parker Koposov, Sergey. E. Li, Ting S. Gnedin, Oleg Y. Bell, Eric F. Carlberg, Raymond G. Cooper, Andrew P. Aguilar, Jessia N. Prieto, Carlos Allende Belokurov, Vasily Silva, Leandro Beraldo e Brooks, David Byström, Amanda Claybaugh, Todd Dawson, Kyle Dey, Arjun Doel, Peter Forero-Romero, Jaime E. Gaztañaga, Enrique Gontcho, Satya Gontcho A Honscheid, Klaus Kisner, T . Kremin, Anthony Lambert, A. Landriau, Martin Guillou, L. Le Levi, Michael E. de la Macorra, Axel Manera, Mark Martini, Paul Medina, Gustavo E. Meisner, Aaron Miquel, Ramon Moustakas, John Myer, Adam D. Najita, Joan Poppett, Claire Prada, Francisco Rezaie, Mehdi Rossi, Graziano Riley, Alex H. Sanchez, Eusebio Schlegel, David Schubnell, Michael Sprayberry, David Tarlé, Gregory Thomas, Guillaume Weaver, Benjamin A. Wechsler, Risa H. Zhou, Rongpu Zou, Hu |
| contents | We present 115 new spectroscopically identified members of the GD-1 tidal stream observed with the 5000-fiber Dark Energy Spectroscopic Instrument (DESI). We confirm the existence of a ``cocoon'' which is a broad (FWHM~2.932 deg ~ 460 pc) and kinematically hot (velocity dispersion, sigma ~ 5-8 km/s) component that surrounds a narrower (FWHM~ 0.353 deg ~ 55) and colder (sigma = 3.09+/-0.76 km/s) thin stream component (based on a median per star velocity precision of 2.7 km/s). The cocoon extends over at least a 30 degree segment of the stream observed by DESI. The thin and cocoon components have similar mean values of [Fe/H]: -2.54+/- 0.04 dex and -2.47+/- 0.06 dex suggestive of a common origin. The data are consistent with the following scenarios for the origin of the cocoon. The progenitor of the GD-1 stream was an accreted globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal stripping of the GC while it was still inside its parent dwarf galaxy; (b) the cocoon is debris from the parent dwarf galaxy; (c) an initially thin GC tidal stream was heated by impacts from dark subhalos in the Milky Way; (d) an initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a combination of some these. Future DESI spectroscopy and detailed modeling may enable us to distinguish between these possible origins. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_06336 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | GD-1 Stellar Stream and Cocoon in the DESI Early Data Release Valluri, Monica Fagrelius, Parker Koposov, Sergey. E. Li, Ting S. Gnedin, Oleg Y. Bell, Eric F. Carlberg, Raymond G. Cooper, Andrew P. Aguilar, Jessia N. Prieto, Carlos Allende Belokurov, Vasily Silva, Leandro Beraldo e Brooks, David Byström, Amanda Claybaugh, Todd Dawson, Kyle Dey, Arjun Doel, Peter Forero-Romero, Jaime E. Gaztañaga, Enrique Gontcho, Satya Gontcho A Honscheid, Klaus Kisner, T . Kremin, Anthony Lambert, A. Landriau, Martin Guillou, L. Le Levi, Michael E. de la Macorra, Axel Manera, Mark Martini, Paul Medina, Gustavo E. Meisner, Aaron Miquel, Ramon Moustakas, John Myer, Adam D. Najita, Joan Poppett, Claire Prada, Francisco Rezaie, Mehdi Rossi, Graziano Riley, Alex H. Sanchez, Eusebio Schlegel, David Schubnell, Michael Sprayberry, David Tarlé, Gregory Thomas, Guillaume Weaver, Benjamin A. Wechsler, Risa H. Zhou, Rongpu Zou, Hu Astrophysics of Galaxies We present 115 new spectroscopically identified members of the GD-1 tidal stream observed with the 5000-fiber Dark Energy Spectroscopic Instrument (DESI). We confirm the existence of a ``cocoon'' which is a broad (FWHM~2.932 deg ~ 460 pc) and kinematically hot (velocity dispersion, sigma ~ 5-8 km/s) component that surrounds a narrower (FWHM~ 0.353 deg ~ 55) and colder (sigma = 3.09+/-0.76 km/s) thin stream component (based on a median per star velocity precision of 2.7 km/s). The cocoon extends over at least a 30 degree segment of the stream observed by DESI. The thin and cocoon components have similar mean values of [Fe/H]: -2.54+/- 0.04 dex and -2.47+/- 0.06 dex suggestive of a common origin. The data are consistent with the following scenarios for the origin of the cocoon. The progenitor of the GD-1 stream was an accreted globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal stripping of the GC while it was still inside its parent dwarf galaxy; (b) the cocoon is debris from the parent dwarf galaxy; (c) an initially thin GC tidal stream was heated by impacts from dark subhalos in the Milky Way; (d) an initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a combination of some these. Future DESI spectroscopy and detailed modeling may enable us to distinguish between these possible origins. |
| title | GD-1 Stellar Stream and Cocoon in the DESI Early Data Release |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2407.06336 |