HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7

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dc.contributor.authorCarignan, C
dc.contributor.authorLibert, Y
dc.contributor.authorLucero, D M
dc.contributor.authorRandriamampandry, T H
dc.contributor.authorJarrett, T H
dc.contributor.authorOosterloo, T A
dc.contributor.authorTollerud, E J
dc.date.accessioned2021-10-08T06:20:06Z
dc.date.available2021-10-08T06:20:06Z
dc.date.issued2016
dc.description.abstractContext. Pisces A and Pisces B are the only two galaxies found via optical imaging and spectroscopy out of 22 HI clouds identified in the GALFAHI survey as dwarf galaxy candidates. Aims: We derive the HI content and kinematics of Pisces A and B. Methods. Our aperture synthesis H observations used the seven-dish Karoo Array Telescope (KAT-7), which is a pathfinder instrument for MeerKAT, the South African precursor to the mid-frequency Square Kilometre Array (SKA-MID). Results: The low rotation velocities of ∼5 km s−1 and ∼10 km s−1 in Pisces A and B, respectively, and their HI content show that they are really dwarf irregular galaxies (dIrr). Despite that small rotation component, it is more the random motions ∼9−11 km s−1 that provide most of the gravitational support, especially in the outer parts. The study of their kinematics, especially the strong gradients of random motions, suggest that those two dwarf galaxies are not yet in equilibrium. Conclusions. These HI- rich galaxies may be indicative of a large population of dwarfs at the limit of detectability. However, such gasrich dwarf galaxies will most likely never be within the virial radius of MW-type galaxies and become subhalo candidates. Systems such as Pisces A and B are more likely to be found at a few Mpc s from MW-type galaxies.
dc.identifier.apacitationCarignan, C., Libert, Y., Lucero, D. M., Randriamampandry, T. H., Jarrett, T. H., Oosterloo, T. A., & Tollerud, E. J. (2016). HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7. <i>Astronomy and Astrophysics</i>, 587(4), L3 - 177. http://hdl.handle.net/11427/34205en_ZA
dc.identifier.chicagocitationCarignan, C, Y Libert, D M Lucero, T H Randriamampandry, T H Jarrett, T A Oosterloo, and E J Tollerud "HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7." <i>Astronomy and Astrophysics</i> 587, 4. (2016): L3 - 177. http://hdl.handle.net/11427/34205en_ZA
dc.identifier.citationCarignan, C., Libert, Y., Lucero, D.M., Randriamampandry, T.H., Jarrett, T.H., Oosterloo, T.A. & Tollerud, E.J. 2016. HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7. <i>Astronomy and Astrophysics.</i> 587(4):L3 - 177. http://hdl.handle.net/11427/34205en_ZA
dc.identifier.issn0004-6361
dc.identifier.issn1432-0746
dc.identifier.ris TY - Journal Article AU - Carignan, C AU - Libert, Y AU - Lucero, D M AU - Randriamampandry, T H AU - Jarrett, T H AU - Oosterloo, T A AU - Tollerud, E J AB - Context. Pisces A and Pisces B are the only two galaxies found via optical imaging and spectroscopy out of 22 HI clouds identified in the GALFAHI survey as dwarf galaxy candidates. Aims: We derive the HI content and kinematics of Pisces A and B. Methods. Our aperture synthesis H observations used the seven-dish Karoo Array Telescope (KAT-7), which is a pathfinder instrument for MeerKAT, the South African precursor to the mid-frequency Square Kilometre Array (SKA-MID). Results: The low rotation velocities of ∼5 km s−1 and ∼10 km s−1 in Pisces A and B, respectively, and their HI content show that they are really dwarf irregular galaxies (dIrr). Despite that small rotation component, it is more the random motions ∼9−11 km s−1 that provide most of the gravitational support, especially in the outer parts. The study of their kinematics, especially the strong gradients of random motions, suggest that those two dwarf galaxies are not yet in equilibrium. Conclusions. These HI- rich galaxies may be indicative of a large population of dwarfs at the limit of detectability. However, such gasrich dwarf galaxies will most likely never be within the virial radius of MW-type galaxies and become subhalo candidates. Systems such as Pisces A and B are more likely to be found at a few Mpc s from MW-type galaxies. DA - 2016 DB - OpenUCT DP - University of Cape Town IS - 4 J1 - Astronomy and Astrophysics LK - https://open.uct.ac.za PY - 2016 SM - 0004-6361 SM - 1432-0746 T1 - HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7 TI - HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7 UR - http://hdl.handle.net/11427/34205 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34205
dc.identifier.vancouvercitationCarignan C, Libert Y, Lucero DM, Randriamampandry TH, Jarrett TH, Oosterloo TA, et al. HI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7. Astronomy and Astrophysics. 2016;587(4):L3 - 177. http://hdl.handle.net/11427/34205.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Astronomy
dc.publisher.facultyFaculty of Science
dc.sourceAstronomy and Astrophysics
dc.source.journalissue4
dc.source.journalvolume587
dc.source.paginationL3 - 177
dc.source.urihttps://dx.doi.org/10.1051/0004-6361/201527910
dc.subject.othergalaxies: dwarf
dc.subject.othergalaxies: individual: Pisces A
dc.subject.othergalaxies: individual: Pisces B
dc.subject.otherISM: kinematics and dynamics
dc.subject.othergalaxies: kinematics and dynamics
dc.titleHI observations of two new dwarf galaxies: Pisces A and B with the SKA Pathfinder KAT-7
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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