TiNy TITANS: THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION

S. Stierwalt, Gurtina Besla, D. Patton, K. Johnson, N. Kallivayalil, M. Putman, G. Privon, G. Ross

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

We introduce TiNy Titans (TNT), the first systematic study of star formation and the subsequent processing of the interstellar medium in interacting dwarf galaxies. Here we present the first results from a multiwavelength observational program based on a sample of 104 dwarf galaxy pairs selected from a range of environments within the spectroscopic portion of the Sloan Digital Sky Survey and caught in various stages of interaction. The TNT dwarf pairs span mass ratios of M<inf>∗,1</inf>/M<inf>∗,2</inf> < 10, projected separations <50 kpc, and pair member masses of 7 < log (M<inf>∗</inf>/M<inf>⊙</inf>) < 9.7. The dwarf-dwarf merger sequence, as defined by TNT at z = 0, demonstrates conclusively and for the first time that the star formation enhancement observed for massive galaxy pairs also extends to the dwarf mass range. Star formation is enhanced in paired dwarfs in otherwise isolated environments by a factor of 2.3 (±0.7) at pair separations <50 kpc relative to unpaired analogs. The enhancement decreases with increasing pair separation and extends out to pair separations as large as 100 kpc. Starbursts, defined by Hα EQW >100 Å, occur in 20% of the TNT dwarf pairs, regardless of environment, compared to only 6%-8% of the matched unpaired dwarfs. Starbursts can be triggered throughout the merger (i.e., out to large pair separations) and not just approaching coalescence. Despite their enhanced star formation and triggered starbursts, most TNT dwarf pairs have similar gas fractions relative to unpaired dwarfs of the same stellar mass. Thus, there may be significant reservoirs of diffuse, non-star-forming neutral gas surrounding the dwarf pairs, or the gas consumption timescales may be long in the starburst phase. The only TNT dwarf pairs with low gas fractions (f<inf>gas</inf> < 0.4) and the only dwarfs, either paired or unpaired, with Hα EQW < 2 Å are found near massive galaxy hosts. We conclude that dwarf-dwarf interactions are significant drivers of galaxy evolution at the low-mass end, but ultimately environment is responsible for the quenching of star formation. This preliminary study is a precursor to an ongoing high-resolution H I and optical imaging program to constrain the spatial distribution of star formation and gas throughout the course of the dwarf-dwarf merger sequence.

Original languageEnglish (US)
Article number2
JournalAstrophysical Journal
Volume805
Issue number1
DOIs
StatePublished - May 20 2015

Fingerprint

Titan
star formation
galaxies
gas
dwarf galaxies
gases
merger
interactions
interacting galaxies
neutral gases
coalescence
stellar mass
mass ratios
coalescing
spatial distribution
quenching
timescale
high resolution
programme

Keywords

  • galaxies: dwarf
  • galaxies: evolution
  • galaxies: interactions
  • galaxies: star formation
  • galaxies: starburst
  • Magellanic Clouds

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Stierwalt, S., Besla, G., Patton, D., Johnson, K., Kallivayalil, N., Putman, M., ... Ross, G. (2015). TiNy TITANS: THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION. Astrophysical Journal, 805(1), [2]. https://doi.org/10.1088/0004-637X/805/1/2

TiNy TITANS : THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION. / Stierwalt, S.; Besla, Gurtina; Patton, D.; Johnson, K.; Kallivayalil, N.; Putman, M.; Privon, G.; Ross, G.

In: Astrophysical Journal, Vol. 805, No. 1, 2, 20.05.2015.

Research output: Contribution to journalArticle

Stierwalt, S, Besla, G, Patton, D, Johnson, K, Kallivayalil, N, Putman, M, Privon, G & Ross, G 2015, 'TiNy TITANS: THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION', Astrophysical Journal, vol. 805, no. 1, 2. https://doi.org/10.1088/0004-637X/805/1/2
Stierwalt, S. ; Besla, Gurtina ; Patton, D. ; Johnson, K. ; Kallivayalil, N. ; Putman, M. ; Privon, G. ; Ross, G. / TiNy TITANS : THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION. In: Astrophysical Journal. 2015 ; Vol. 805, No. 1.
@article{d63a4ec45b2b4241ba68683806ae84e2,
title = "TiNy TITANS: THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION",
abstract = "We introduce TiNy Titans (TNT), the first systematic study of star formation and the subsequent processing of the interstellar medium in interacting dwarf galaxies. Here we present the first results from a multiwavelength observational program based on a sample of 104 dwarf galaxy pairs selected from a range of environments within the spectroscopic portion of the Sloan Digital Sky Survey and caught in various stages of interaction. The TNT dwarf pairs span mass ratios of M∗,1/M∗,2 < 10, projected separations <50 kpc, and pair member masses of 7 < log (M∗/M⊙) < 9.7. The dwarf-dwarf merger sequence, as defined by TNT at z = 0, demonstrates conclusively and for the first time that the star formation enhancement observed for massive galaxy pairs also extends to the dwarf mass range. Star formation is enhanced in paired dwarfs in otherwise isolated environments by a factor of 2.3 (±0.7) at pair separations <50 kpc relative to unpaired analogs. The enhancement decreases with increasing pair separation and extends out to pair separations as large as 100 kpc. Starbursts, defined by Hα EQW >100 {\AA}, occur in 20{\%} of the TNT dwarf pairs, regardless of environment, compared to only 6{\%}-8{\%} of the matched unpaired dwarfs. Starbursts can be triggered throughout the merger (i.e., out to large pair separations) and not just approaching coalescence. Despite their enhanced star formation and triggered starbursts, most TNT dwarf pairs have similar gas fractions relative to unpaired dwarfs of the same stellar mass. Thus, there may be significant reservoirs of diffuse, non-star-forming neutral gas surrounding the dwarf pairs, or the gas consumption timescales may be long in the starburst phase. The only TNT dwarf pairs with low gas fractions (fgas < 0.4) and the only dwarfs, either paired or unpaired, with Hα EQW < 2 {\AA} are found near massive galaxy hosts. We conclude that dwarf-dwarf interactions are significant drivers of galaxy evolution at the low-mass end, but ultimately environment is responsible for the quenching of star formation. This preliminary study is a precursor to an ongoing high-resolution H I and optical imaging program to constrain the spatial distribution of star formation and gas throughout the course of the dwarf-dwarf merger sequence.",
keywords = "galaxies: dwarf, galaxies: evolution, galaxies: interactions, galaxies: star formation, galaxies: starburst, Magellanic Clouds",
author = "S. Stierwalt and Gurtina Besla and D. Patton and K. Johnson and N. Kallivayalil and M. Putman and G. Privon and G. Ross",
year = "2015",
month = "5",
day = "20",
doi = "10.1088/0004-637X/805/1/2",
language = "English (US)",
volume = "805",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - TiNy TITANS

T2 - THE ROLE OF DWARF-DWARF INTERACTIONS IN LOW-MASS GALAXY EVOLUTION

AU - Stierwalt, S.

AU - Besla, Gurtina

AU - Patton, D.

AU - Johnson, K.

AU - Kallivayalil, N.

AU - Putman, M.

AU - Privon, G.

AU - Ross, G.

PY - 2015/5/20

Y1 - 2015/5/20

N2 - We introduce TiNy Titans (TNT), the first systematic study of star formation and the subsequent processing of the interstellar medium in interacting dwarf galaxies. Here we present the first results from a multiwavelength observational program based on a sample of 104 dwarf galaxy pairs selected from a range of environments within the spectroscopic portion of the Sloan Digital Sky Survey and caught in various stages of interaction. The TNT dwarf pairs span mass ratios of M∗,1/M∗,2 < 10, projected separations <50 kpc, and pair member masses of 7 < log (M∗/M⊙) < 9.7. The dwarf-dwarf merger sequence, as defined by TNT at z = 0, demonstrates conclusively and for the first time that the star formation enhancement observed for massive galaxy pairs also extends to the dwarf mass range. Star formation is enhanced in paired dwarfs in otherwise isolated environments by a factor of 2.3 (±0.7) at pair separations <50 kpc relative to unpaired analogs. The enhancement decreases with increasing pair separation and extends out to pair separations as large as 100 kpc. Starbursts, defined by Hα EQW >100 Å, occur in 20% of the TNT dwarf pairs, regardless of environment, compared to only 6%-8% of the matched unpaired dwarfs. Starbursts can be triggered throughout the merger (i.e., out to large pair separations) and not just approaching coalescence. Despite their enhanced star formation and triggered starbursts, most TNT dwarf pairs have similar gas fractions relative to unpaired dwarfs of the same stellar mass. Thus, there may be significant reservoirs of diffuse, non-star-forming neutral gas surrounding the dwarf pairs, or the gas consumption timescales may be long in the starburst phase. The only TNT dwarf pairs with low gas fractions (fgas < 0.4) and the only dwarfs, either paired or unpaired, with Hα EQW < 2 Å are found near massive galaxy hosts. We conclude that dwarf-dwarf interactions are significant drivers of galaxy evolution at the low-mass end, but ultimately environment is responsible for the quenching of star formation. This preliminary study is a precursor to an ongoing high-resolution H I and optical imaging program to constrain the spatial distribution of star formation and gas throughout the course of the dwarf-dwarf merger sequence.

AB - We introduce TiNy Titans (TNT), the first systematic study of star formation and the subsequent processing of the interstellar medium in interacting dwarf galaxies. Here we present the first results from a multiwavelength observational program based on a sample of 104 dwarf galaxy pairs selected from a range of environments within the spectroscopic portion of the Sloan Digital Sky Survey and caught in various stages of interaction. The TNT dwarf pairs span mass ratios of M∗,1/M∗,2 < 10, projected separations <50 kpc, and pair member masses of 7 < log (M∗/M⊙) < 9.7. The dwarf-dwarf merger sequence, as defined by TNT at z = 0, demonstrates conclusively and for the first time that the star formation enhancement observed for massive galaxy pairs also extends to the dwarf mass range. Star formation is enhanced in paired dwarfs in otherwise isolated environments by a factor of 2.3 (±0.7) at pair separations <50 kpc relative to unpaired analogs. The enhancement decreases with increasing pair separation and extends out to pair separations as large as 100 kpc. Starbursts, defined by Hα EQW >100 Å, occur in 20% of the TNT dwarf pairs, regardless of environment, compared to only 6%-8% of the matched unpaired dwarfs. Starbursts can be triggered throughout the merger (i.e., out to large pair separations) and not just approaching coalescence. Despite their enhanced star formation and triggered starbursts, most TNT dwarf pairs have similar gas fractions relative to unpaired dwarfs of the same stellar mass. Thus, there may be significant reservoirs of diffuse, non-star-forming neutral gas surrounding the dwarf pairs, or the gas consumption timescales may be long in the starburst phase. The only TNT dwarf pairs with low gas fractions (fgas < 0.4) and the only dwarfs, either paired or unpaired, with Hα EQW < 2 Å are found near massive galaxy hosts. We conclude that dwarf-dwarf interactions are significant drivers of galaxy evolution at the low-mass end, but ultimately environment is responsible for the quenching of star formation. This preliminary study is a precursor to an ongoing high-resolution H I and optical imaging program to constrain the spatial distribution of star formation and gas throughout the course of the dwarf-dwarf merger sequence.

KW - galaxies: dwarf

KW - galaxies: evolution

KW - galaxies: interactions

KW - galaxies: star formation

KW - galaxies: starburst

KW - Magellanic Clouds

UR - http://www.scopus.com/inward/record.url?scp=84930205345&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84930205345&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/805/1/2

DO - 10.1088/0004-637X/805/1/2

M3 - Article

AN - SCOPUS:84930205345

VL - 805

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 2

ER -