AGC198606: A gas-bearing dark matter minihalo?

E. A. K. Adams; Y. Faerman; W. F. Janesh; S. Janowiecki; T. A. Oosterloo; K. L. Rhode; R. Giovanelli; M. P. Haynes; J. J. Salzer; A. Sternberg; J. M. Cannon; R. R. Munoz

doi:10.1051/0004-6361/201425211

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AGC198606: A gas-bearing dark matter minihalo?

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AGC198606: A gas-bearing dark matter minihalo?

E. A. K. Adams, Y. Faerman, W. F. Janesh, S. Janowiecki, T. A. Oosterloo, K. L. Rhode, R. Giovanelli, M. P. Haynes, J. J. Salzer, A. Sternberg, …

Astronomy and astrophysics (Berlin), Vol.573, p.L3

01/01/2015

DOI: 10.1051/0004-6361/201425211

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Abstract

We present neutral hydrogen (HI) imaging observations with the Westerbork Synthesis Radio Telescope of AGC198606, an HI cloud discovered in the ALFALFA 21cm survey. This object is of particular note as it is located 16 km s(-1) and 1 degrees.2 from the gas-bearing ultra-faint dwarf galaxy Leo T while having a similar HI linewidth and approximately twice the flux density. The HI imaging observations reveal a smooth, undisturbed HI morphology with a full extent of 23' x 16' at the 5 x 10(18) atoms cm(-2) level. The velocity field of AGC198606 shows ordered motion with a gradient of similar to 25 km s(-1) across similar to 20'. The global velocity dispersion is 9.3 km s(-1) with no evidence for a narrow spectral component. No optical counterpart to AGC198606 is detected. The distance to AGC198606 is unknown, and we consider several different scenarios: physical association with Leo T, a minihalo at a distance of similar to 150 kpc based on the models of Faerman et al. (2013, ApJ, 777, 119), and a cloud in the Galactic halo. At a distance of 420 kpc, AGC198606 would have an Hi mass of 6.2 x 10(5) M-circle dot, an HI radius of 1.4 kpc, and a dynamical mass within the HI extent of 1.5 x 10(8) M-circle dot.

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Title: Subtitle: AGC198606: A gas-bearing dark matter minihalo?
Creators: E. A. K. Adams - Netherlands Institute for Radio Astronomy
Y. Faerman - Tel Aviv University
W. F. Janesh - Indiana University Bloomington
S. Janowiecki - Indiana University Bloomington
T. A. Oosterloo - Netherlands Institute for Radio Astronomy
K. L. Rhode - Indiana University Bloomington
R. Giovanelli - Cornell University
M. P. Haynes - Cornell University
J. J. Salzer - Indiana University Bloomington
A. Sternberg - Tel Aviv University
J. M. Cannon - Macalester College
R. R. Munoz - University of Chile
Resource Type: Journal article
Publication Details: Astronomy and astrophysics (Berlin), Vol.573, p.L3
Publisher: Edp Sciences S A
DOI: 10.1051/0004-6361/201425211
ISSN: 0004-6361
eISSN: 1432-0746
Number of pages: 4
Grant note: AST-0847109 / NSF CAREER award; National Science Foundation (NSF); NSF - Office of the Director (OD) 1211683 / Division Of Astronomical Sciences; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS) 1120013 / FONDECYT; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); CONICYT FONDECYT ACT-1122 / CONICYT Anillo project; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); CONICYT PIA/ANILLOS PFB-06 / project BASAL; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); CONICYT PIA/BASAL Netherlands Foundation for Scientific Research (NWO); Netherlands Organization for Scientific Research (NWO) Brinson Foundation AST-0607007; AST-1107390; AST-1211683 / NSF; National Science Foundation (NSF)
Language: English
Date published: 01/01/2015
Academic Unit: Physics and Astronomy
Record Identifier: 9984627315802771

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