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Two Orders of Magnitude Variation in the Star Formation Efficiency across the Premerger Galaxy NGC 2276

Tomičić, Neven ; Hughes, Annie ; Kreckel, Kathryn ; Renaud, Florent LU ; Pety, Jérôme ; Schinnerer, Eva ; Saito, Toshiki ; Querejeta, Miguel ; Faesi, Christopher M. and Garcia-Burillo, Santiago (2018) In Astrophysical Journal Letters 869(2).
Abstract

We present the first spatially resolved (∼0.5 kpc) measurements of the molecular gas depletion time τ depl across the disk of the interacting spiral galaxy NGC 2276, a system with an asymmetric morphology in various star formation rate (SFR) tracers. To estimate τ depl, we use new NOEMA observations of the 12CO(1-0) emission tracing the bulk molecular gas reservoir in NGC 2276, and extinction-corrected Hα measurements obtained with the PMAS/PPaK integral field unit for robust estimates of the SFR. We find a systematic decrease in τ depl of 1-1.5 dex across the disk of NGC 2276, with a further, abrupt drop in τ depl of ∼1 dex along the galaxy's western edge. The global τ... (More)

We present the first spatially resolved (∼0.5 kpc) measurements of the molecular gas depletion time τ depl across the disk of the interacting spiral galaxy NGC 2276, a system with an asymmetric morphology in various star formation rate (SFR) tracers. To estimate τ depl, we use new NOEMA observations of the 12CO(1-0) emission tracing the bulk molecular gas reservoir in NGC 2276, and extinction-corrected Hα measurements obtained with the PMAS/PPaK integral field unit for robust estimates of the SFR. We find a systematic decrease in τ depl of 1-1.5 dex across the disk of NGC 2276, with a further, abrupt drop in τ depl of ∼1 dex along the galaxy's western edge. The global τ depl in NGC 2776 is τdepl = 0.55 Gyr, consistent with literature measurements for the nearby galaxy population. Such a large range in τ depl on subkiloparsec scales has never previously been observed within an individual isolated or premerger system. When using a metallicity-dependent molecular gas conversion factor the variation decreases by 0.5 dex. We attribute the variation in τ depl to the influence of galactic-scale tidal forces and ram pressure on NGC 2276's molecular interstellar medium. Our observations add to the growing body of numerical and observational evidence that galaxy-galaxy interactions significantly modify the molecular gas properties and star-forming activity within galactic disks throughout the interaction, and not just during the final merger phase.

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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
galaxies: individual (NGC 2276), galaxies: ISM, galaxies: star formation
in
Astrophysical Journal Letters
volume
869
issue
2
article number
L38
publisher
IOP Publishing
external identifiers
  • scopus:85059870695
ISSN
2041-8205
DOI
10.3847/2041-8213/aaf810
language
English
LU publication?
yes
id
dd1a3d1f-8538-4f5e-abc6-bade0211d972
date added to LUP
2019-01-24 10:23:38
date last changed
2021-10-06 03:56:22
@article{dd1a3d1f-8538-4f5e-abc6-bade0211d972,
  abstract     = {<p>We present the first spatially resolved (∼0.5 kpc) measurements of the molecular gas depletion time τ <sub>depl</sub> across the disk of the interacting spiral galaxy NGC 2276, a system with an asymmetric morphology in various star formation rate (SFR) tracers. To estimate τ <sub>depl</sub>, we use new NOEMA observations of the <sup>12</sup>CO(1-0) emission tracing the bulk molecular gas reservoir in NGC 2276, and extinction-corrected Hα measurements obtained with the PMAS/PPaK integral field unit for robust estimates of the SFR. We find a systematic decrease in τ <sub>depl</sub> of 1-1.5 dex across the disk of NGC 2276, with a further, abrupt drop in τ <sub>depl</sub> of ∼1 dex along the galaxy's western edge. The global τ <sub>depl</sub> in NGC 2776 is τ<sub>depl</sub> = 0.55 Gyr, consistent with literature measurements for the nearby galaxy population. Such a large range in τ <sub>depl</sub> on subkiloparsec scales has never previously been observed within an individual isolated or premerger system. When using a metallicity-dependent molecular gas conversion factor the variation decreases by 0.5 dex. We attribute the variation in τ <sub>depl</sub> to the influence of galactic-scale tidal forces and ram pressure on NGC 2276's molecular interstellar medium. Our observations add to the growing body of numerical and observational evidence that galaxy-galaxy interactions significantly modify the molecular gas properties and star-forming activity within galactic disks throughout the interaction, and not just during the final merger phase.</p>},
  author       = {Tomičić, Neven and Hughes, Annie and Kreckel, Kathryn and Renaud, Florent and Pety, Jérôme and Schinnerer, Eva and Saito, Toshiki and Querejeta, Miguel and Faesi, Christopher M. and Garcia-Burillo, Santiago},
  issn         = {2041-8205},
  language     = {eng},
  month        = {12},
  number       = {2},
  publisher    = {IOP Publishing},
  series       = {Astrophysical Journal Letters},
  title        = {Two Orders of Magnitude Variation in the Star Formation Efficiency across the Premerger Galaxy NGC 2276},
  url          = {http://dx.doi.org/10.3847/2041-8213/aaf810},
  doi          = {10.3847/2041-8213/aaf810},
  volume       = {869},
  year         = {2018},
}