Image de couverture de livre

Characterizing the GD-1 Stream with DESI DR2 Data: Thin Stream and Hot Cocoon

Fuente: arXiv

Enregistré dans:

Détails bibliographiques
Auteurs principaux:	Jarvis, Emma, Li, Ting S., Koposov, Sergey E., Carlberg, Raymond G., Valluri, Monica, Mohammed, Nasser, Aguilar, J., Ahlen, S., Prieto, Carlos Allende, Silva, Leandro Beraldo e, Bianchi, D., Brooks, D., Byström, Amanda, Claybaugh, T., Cooper, A. P., Cuceu, A., de la Macorra, A., Dey, Arjun, Dey, Biprateep, Doel, P., Forero-Romero, J. E., Gaztañaga, E., Gnedin, Oleg Y., Gontcho, Satya Gontcho A, Gutierrez, G., Honscheid, K., Joyce, R., Kehoe, R., Kisner, T., Kizhuprakkat, Namitha, Kremin, A., Lambert, Mika, Landriau, M., Guillou, L. Le, Medina, Gustavo E., Meisner, A., Miquel, R., Nadathur, S., Najita, Joan, Palanque-Delabrouille, N., Percival, W. J., Prada, F., Pérez-Ràfols, I., Qiu, Tian, Riley, Alexander H., Rockosi, Constance M., Rossi, G., Sanchez, E., Sandford, Nathan, Schlafly, E. F., Schlegel, D., Silber, J., Sprayberry, D., Tarlé, G., Weaver, B. A., Zhou, R., Zou, H.
Format:	Preprint
Publié:	2026
Sujets:	Astrophysics of Galaxies
Accès en ligne:	Acceder al recurso
Tags:	Ajouter un tag Pas de tags, Soyez le premier à ajouter un tag!

_version_	1866908987768700928
author	Jarvis, Emma Li, Ting S. Koposov, Sergey E. Carlberg, Raymond G. Valluri, Monica Mohammed, Nasser Aguilar, J. Ahlen, S. Prieto, Carlos Allende Silva, Leandro Beraldo e Bianchi, D. Brooks, D. Byström, Amanda Claybaugh, T. Cooper, A. P. Cuceu, A. de la Macorra, A. Dey, Arjun Dey, Biprateep Doel, P. Forero-Romero, J. E. Gaztañaga, E. Gnedin, Oleg Y. Gontcho, Satya Gontcho A Gutierrez, G. Honscheid, K. Joyce, R. Kehoe, R. Kisner, T. Kizhuprakkat, Namitha Kremin, A. Lambert, Mika Landriau, M. Guillou, L. Le Medina, Gustavo E. Meisner, A. Miquel, R. Nadathur, S. Najita, Joan Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Qiu, Tian Riley, Alexander H. Rockosi, Constance M. Rossi, G. Sanchez, E. Sandford, Nathan Schlafly, E. F. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H.
author_facet	Jarvis, Emma Li, Ting S. Koposov, Sergey E. Carlberg, Raymond G. Valluri, Monica Mohammed, Nasser Aguilar, J. Ahlen, S. Prieto, Carlos Allende Silva, Leandro Beraldo e Bianchi, D. Brooks, D. Byström, Amanda Claybaugh, T. Cooper, A. P. Cuceu, A. de la Macorra, A. Dey, Arjun Dey, Biprateep Doel, P. Forero-Romero, J. E. Gaztañaga, E. Gnedin, Oleg Y. Gontcho, Satya Gontcho A Gutierrez, G. Honscheid, K. Joyce, R. Kehoe, R. Kisner, T. Kizhuprakkat, Namitha Kremin, A. Lambert, Mika Landriau, M. Guillou, L. Le Medina, Gustavo E. Meisner, A. Miquel, R. Nadathur, S. Najita, Joan Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Qiu, Tian Riley, Alexander H. Rockosi, Constance M. Rossi, G. Sanchez, E. Sandford, Nathan Schlafly, E. F. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H.
contents	GD-1 is among the longest, coldest stellar streams in the Milky Way, making it an ideal target for probing dark matter substructure through dynamical heating. We present a catalog of 608 spectroscopically confirmed GD-1 members from the first three years of Dark Energy Spectroscopic Instrument (DESI) observations. This constitutes the largest homogeneous spectroscopic sample of GD-1, doubling the number of members previously available only through heterogeneous compilations combining multiple surveys with different systematics. Using these data, we derive updated stream tracks in sky position, proper motion, and radial velocity that extend over $100^\circ$ of the stream. We apply a Gaussian mixture model to decompose the stream into a dynamically cold thin component ($σ_V = 2.49\pm 0.28$ km s$^{-1}$, width $= 0.23\pm0.01^\circ$) and a kinematically hot cocoon ($σ_V = 6.13\pm0.75$ km s$^{-1}$, width $= 2.18\pm0.17^\circ$). The cocoon contains $\sim30\%$ of members and its velocity dispersion is consistent with $\sim11$ Gyr of heating by cold dark matter subhalos. We also detect a large proper motion dispersion ($41.36\pm4.98$ km s$^{-1}$) along the stream direction in the cocoon component. This feature indicates a significant line-of-sight distance spread in the cocoon, and its origin will be further explored in a forthcoming paper. These measurements demonstrate the power of DESI spectroscopy for characterizing the multi-component phase-space structure of stellar streams and constraining small-scale dark matter substructure.
format	Preprint
id	arxiv_https___arxiv_org_abs_2604_20958
institution	arXiv
publishDate	2026
record_format	arxiv
spellingShingle	Characterizing the GD-1 Stream with DESI DR2 Data: Thin Stream and Hot Cocoon Jarvis, Emma Li, Ting S. Koposov, Sergey E. Carlberg, Raymond G. Valluri, Monica Mohammed, Nasser Aguilar, J. Ahlen, S. Prieto, Carlos Allende Silva, Leandro Beraldo e Bianchi, D. Brooks, D. Byström, Amanda Claybaugh, T. Cooper, A. P. Cuceu, A. de la Macorra, A. Dey, Arjun Dey, Biprateep Doel, P. Forero-Romero, J. E. Gaztañaga, E. Gnedin, Oleg Y. Gontcho, Satya Gontcho A Gutierrez, G. Honscheid, K. Joyce, R. Kehoe, R. Kisner, T. Kizhuprakkat, Namitha Kremin, A. Lambert, Mika Landriau, M. Guillou, L. Le Medina, Gustavo E. Meisner, A. Miquel, R. Nadathur, S. Najita, Joan Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Qiu, Tian Riley, Alexander H. Rockosi, Constance M. Rossi, G. Sanchez, E. Sandford, Nathan Schlafly, E. F. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H. Astrophysics of Galaxies GD-1 is among the longest, coldest stellar streams in the Milky Way, making it an ideal target for probing dark matter substructure through dynamical heating. We present a catalog of 608 spectroscopically confirmed GD-1 members from the first three years of Dark Energy Spectroscopic Instrument (DESI) observations. This constitutes the largest homogeneous spectroscopic sample of GD-1, doubling the number of members previously available only through heterogeneous compilations combining multiple surveys with different systematics. Using these data, we derive updated stream tracks in sky position, proper motion, and radial velocity that extend over $100^\circ$ of the stream. We apply a Gaussian mixture model to decompose the stream into a dynamically cold thin component ($σ_V = 2.49\pm 0.28$ km s$^{-1}$, width $= 0.23\pm0.01^\circ$) and a kinematically hot cocoon ($σ_V = 6.13\pm0.75$ km s$^{-1}$, width $= 2.18\pm0.17^\circ$). The cocoon contains $\sim30\%$ of members and its velocity dispersion is consistent with $\sim11$ Gyr of heating by cold dark matter subhalos. We also detect a large proper motion dispersion ($41.36\pm4.98$ km s$^{-1}$) along the stream direction in the cocoon component. This feature indicates a significant line-of-sight distance spread in the cocoon, and its origin will be further explored in a forthcoming paper. These measurements demonstrate the power of DESI spectroscopy for characterizing the multi-component phase-space structure of stellar streams and constraining small-scale dark matter substructure.
title	Characterizing the GD-1 Stream with DESI DR2 Data: Thin Stream and Hot Cocoon
topic	Astrophysics of Galaxies
url	https://arxiv.org/abs/2604.20958