Two Orders of Magnitude Variation in the Star Formation Efficiency across the Premerger Galaxy NGC 2276
(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.
(Less)
- author
- Tomičić, Neven ; Hughes, Annie ; Kreckel, Kathryn ; Renaud, Florent LU ; Pety, Jérôme ; Schinnerer, Eva ; Saito, Toshiki ; Querejeta, Miguel ; Faesi, Christopher M. and Garcia-Burillo, Santiago
- organization
- publishing date
- 2018-12-20
- 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
- 2024-03-18 23:43:06
@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}}, keywords = {{galaxies: individual (NGC 2276); galaxies: ISM; galaxies: star formation}}, 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}}, }