Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3377521

Disentangling the Distant Stellar Halo Using K Giants in DESI Year 3 Data

Kizhuprakkat, Namitha [National Tsing Hua Univ., Hsinchu (Taiwan)] (ORCID:0000000308538887)·Cooper, Andrew P. [National Tsing Hua Univ., Hsinchu (Taiwan)] (ORCID:000000018274158X)·Wang, Wenting [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000257627571)·Byström, Amanda [Univ. of Edinburgh, Scotland (United Kingdom)] (ORCID:0000000256898791)·Najita, Joan [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:000000025758150X)·Koposov, Sergey E. [Univ. of Edinburgh, Scotland (United Kingdom); Univ. of Cambridge (United Kingdom)] (ORCID:000000032644135X)·Thomas, Guillaume [Instituto de Astrofísica de Canarias, Tenerife (Spain)] (ORCID:0000000224685521)·Li, Songting [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000264698263)·Zhang, Ruizhi [Instituto de Astrofísica de Canarias, Tenerife (Spain); Univ. of La Laguna (Spain)] (ORCID:0009000813191084)·Allende Prieto, Carlos [Instituto de Astrofísica de Canarias, Tenerife (Spain); Univ. of La Laguna (Spain)] (ORCID:000000020084572X)·Lambert, Mika [Univ. of California, Santa Cruz, CA (United States)] (ORCID:0000000225278899)·Gnedin, Oleg Y. [Univ. of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000198529954)·Riley, Alexander H. [Lund Univ. (Sweden)] (ORCID:0000000158055766)·Aguilar, Jessica N. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:000000030822452X)·Ahlen, Steven [Boston Univ., MA (United States)] (ORCID:0000000160987247)·Bianchi, Davide [Univ. degli Studi di Milano (Italy)] (ORCID:0000000197120006)·Brooks, David [Univ. College London (United Kingdom)] (ORCID:0000000284585047)·Claybaugh, Todd [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)]·de la Macorra, Axel [Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)] (ORCID:0000000217691640)·Doel, Peter [Univ. College London (United Kingdom)] (ORCID:0000000263974457)·Gaztañaga, Enrique [Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona (Spain); Univ. of Portsmouth (United Kingdom); Institute of Space Sciences, Barcelona (Spain)] (ORCID:0000000196320815)·Gontcho A Gontcho, Satya [Univ. of Virginia, Charlottesville, VA (United States)] (ORCID:000000033142233X)·Gutierrez, Gaston [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)] (ORCID:0000000308250517)·Joyce, Dick [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000302015241)·Kehoe, Robert [Southern Methodist Univ., Dallas, TX (United States)] (ORCID:000000027101697X)·Kisner, Theodore [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000335107134)·Kremin, Anthony [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000163567424)·Landriau, Martin [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000318388528)·Le Guillou, Laurent [Sorbonne Univ., Paris (France)] (ORCID:0000000171788868)·Manera, Marc [Univ. Autonoma de Barcelona (Spain); Inst. for High Energy Physics (IFAE), Barcelona (Spain)] (ORCID:0000000349628934)·Meisner, Aaron [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000211257384)·Miquel, Ramon [Inst. for High Energy Physics (IFAE), Barcelona (Spain); Univ. Autonoma de Barcelona (Spain). Inst. Catalana de Recerca i Estudis Avancats (ICREA)] (ORCID:0000000266104836)·Percival, Will [Univ. of Waterloo, ON (Canada); Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada)] (ORCID:0000000206445727)·Prada, Francisco [Instituto de Astrofísica de Andalucía (CSIC), Granada (Spain)] (ORCID:0000000171458674)·Pérez-Ràfols, Ignasi [Univ. Politecnica de Catalunya (Spain)] (ORCID:0000000169790125)·Rossi, Graziano [Sejong Univ., Seoul (Korea, Republic of)]·Sanchez, Eusebio [Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain)] (ORCID:0000000296468198)·Schlegel, David [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000250425088)·Schubnell, Michael [Univ. of Michigan, Ann Arbor, MI (United States)]·Sharples, Ray [Durham Univ. (United Kingdom)] (ORCID:0000000334498583)·Silber, Joseph H. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000234610320)·Sprayberry, David [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000175836441)·Tarlé, Gregory [Univ. of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000317040781)·Weaver, Benjamin A. [NSF NOIRLab, Tucson, AZ (United States)]·Zou, Hu [Chinese Academy of Sciences (CAS), Beijing (China)] (ORCID:0000000266843997)
View original source ↗Read source document ↗Export metadata ↓

Abstract

We present a sample of 88,959 K giants from Dark Energy Spectroscopic Instrument Milky Way Survey Year 3 data, which we use to characterize the chemo-dynamical properties of the stellar halo at Galactocentric distances of 12 to ∼100 kpc. Using HDBSCAN, we identify five prominent stellar halo substructures: Aleph, the Sagittarius stream, Gaia-Sausage-Enceladus (GSE), Cetus-Palca, and the Orphan–Chenab stream. We present the properties of each of these structures as they appear in our catalog, and examine how uncertainties on distance affect the characterization of substructure with this approach. We also examine regions associated with previously reported overdensities (such as the Virgo Overdensities and the Sagittarius spur) that we do not recover with HDBSCAN. The size and distance range of our catalog allows us to explore in detail the residual stellar halo, comprising stars that we do not associate with any substructure. We find that samples of ∼2000 outer halo stars with both highly prograde and highly retrograde angular momenta have similar metallicity distribution functions (MDFs), which do not resemble the MDFs of either GSE or Sagittarius. Both the prograde and retrograde residual halo MDFs are bimodal, with a metal-poor peak at [Fe/H] ∼ −2 and a metal-rich peak at [Fe/H] ∼ −1.3 (prograde) or −1.5 (retrograde). The MDF for lower-angular-momentum residual halo K giants does not show clear evidence for a metal-poor peak, and broadly resembles the MDF of GSE, even at much lower binding energies than GSE itself. We discuss possible interpretations of these findings for GSE accretion scenarios.

Explore related subjects

79 ASTRONOMY AND ASTROPHYSICS

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kizhuprakkat, Namitha [National Tsing Hua Univ., Hsinchu (Taiwan)] (ORCID:0000000308538887), Cooper, Andrew P. [National Tsing Hua Univ., Hsinchu (Taiwan)] (ORCID:000000018274158X), Wang, Wenting [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000257627571), Byström, Amanda [Univ. of Edinburgh, Scotland (United Kingdom)] (ORCID:0000000256898791), Najita, Joan [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:000000025758150X), Koposov, Sergey E. [Univ. of Edinburgh, Scotland (United Kingdom); Univ. of Cambridge (United Kingdom)] (ORCID:000000032644135X), Thomas, Guillaume [Instituto de Astrofísica de Canarias, Tenerife (Spain)] (ORCID:0000000224685521), Li, Songting [Shanghai Jiao Tong Univ. (China)] (ORCID:0000000264698263), Zhang, Ruizhi [Instituto de Astrofísica de Canarias, Tenerife (Spain); Univ. of La Laguna (Spain)] (ORCID:0009000813191084), Allende Prieto, Carlos [Instituto de Astrofísica de Canarias, Tenerife (Spain); Univ. of La Laguna (Spain)] (ORCID:000000020084572X), Lambert, Mika [Univ. of California, Santa Cruz, CA (United States)] (ORCID:0000000225278899), Gnedin, Oleg Y. [Univ. of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000198529954), Riley, Alexander H. [Lund Univ. (Sweden)] (ORCID:0000000158055766), Aguilar, Jessica N. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:000000030822452X), Ahlen, Steven [Boston Univ., MA (United States)] (ORCID:0000000160987247), Bianchi, Davide [Univ. degli Studi di Milano (Italy)] (ORCID:0000000197120006), Brooks, David [Univ. College London (United Kingdom)] (ORCID:0000000284585047), Claybaugh, Todd [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], de la Macorra, Axel [Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)] (ORCID:0000000217691640), Doel, Peter [Univ. College London (United Kingdom)] (ORCID:0000000263974457), Gaztañaga, Enrique [Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona (Spain); Univ. of Portsmouth (United Kingdom); Institute of Space Sciences, Barcelona (Spain)] (ORCID:0000000196320815), Gontcho A Gontcho, Satya [Univ. of Virginia, Charlottesville, VA (United States)] (ORCID:000000033142233X), Gutierrez, Gaston [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)] (ORCID:0000000308250517), Joyce, Dick [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000302015241), Kehoe, Robert [Southern Methodist Univ., Dallas, TX (United States)] (ORCID:000000027101697X), Kisner, Theodore [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000335107134), Kremin, Anthony [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000163567424), Landriau, Martin [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000318388528), Le Guillou, Laurent [Sorbonne Univ., Paris (France)] (ORCID:0000000171788868), Manera, Marc [Univ. Autonoma de Barcelona (Spain); Inst. for High Energy Physics (IFAE), Barcelona (Spain)] (ORCID:0000000349628934), Meisner, Aaron [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000211257384), Miquel, Ramon [Inst. for High Energy Physics (IFAE), Barcelona (Spain); Univ. Autonoma de Barcelona (Spain). Inst. Catalana de Recerca i Estudis Avancats (ICREA)] (ORCID:0000000266104836), Percival, Will [Univ. of Waterloo, ON (Canada); Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada)] (ORCID:0000000206445727), Prada, Francisco [Instituto de Astrofísica de Andalucía (CSIC), Granada (Spain)] (ORCID:0000000171458674), Pérez-Ràfols, Ignasi [Univ. Politecnica de Catalunya (Spain)] (ORCID:0000000169790125), Rossi, Graziano [Sejong Univ., Seoul (Korea, Republic of)], Sanchez, Eusebio [Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain)] (ORCID:0000000296468198), Schlegel, David [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000250425088), Schubnell, Michael [Univ. of Michigan, Ann Arbor, MI (United States)], Sharples, Ray [Durham Univ. (United Kingdom)] (ORCID:0000000334498583), Silber, Joseph H. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000234610320), Sprayberry, David [NSF NOIRLab, Tucson, AZ (United States)] (ORCID:0000000175836441), Tarlé, Gregory [Univ. of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000317040781), Weaver, Benjamin A. [NSF NOIRLab, Tucson, AZ (United States)], Zou, Hu [Chinese Academy of Sciences (CAS), Beijing (China)] (ORCID:0000000266843997). 2026-07-17. Disentangling the Distant Stellar Halo Using K Giants in DESI Year 3 Data. https://doi.org/10.3847/1538-4357%2Fae7f15

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Dust Survival in Galactic Winds

This repository contains three-dimensional volumetric data from an Eulerian hydrodynamical simulation (conducted on a uniform Cartesian grid) generated by the Cholla hydrodynamics code. The datasets contain snapshots (full-grid, projections, and slices) in the HDF5 format of a multi-phase medium in which a hot, diffuse, dust-free background wind accelerates a cool, dense cloud of gas and dust. This scenario is intended to represent a supernova-driven galactic outflow, in which hot supernova winds are thought to accelerate cool interstellar medium material out of the galactic disk into the surrounding circumgalactic medium. There are three separate datasets for simulations corresponding to three cloud evolutionary scenarios: long-term cloud survival (surv), marginal cloud survival (disr), and cloud destruction (dest). Projection and slice images of the simulations are also included in this repository.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Unraveling TeV halos with the Cherenkov Telescope Array

Pulsars are observed to emit bright and spatially extended gamma-ray emission at multi-TeV energies. These so-called "TeV halos" are now understood to be a nearly universal feature of middle-aged pulsars. However, many of the key physical processes that govern these systems, particularly those affecting particle diffusion, remain poorly constrained. We aim to evaluate the ability of the Cherenkov Telescope Array (CTA) to probe the physical properties of TeV halos, with a focus on the nearby and well-studied case of the Geminga pulsar. We simulate gamma-ray emission from various TeV halo models, incorporating different assumptions for the injected electron spectrum, spin-down evolution, and energy-dependent diffusion. These models are then used to forecast CTA's sensitivity to spectral and spatial differences, based on realistic mock observations and instrument response simulations. We find that CTA will be able to distinguish between a wide range of TeV halo models that are currently consistent with existing data. In particular, CTA observations can constrain the normalization, energy dependence, and spatial extent of the diffusion coefficient surrounding Geminga, as well as the spectral shape of the injected electron population.

79 ASTRONOMY AND ASTROPHYSICS↗