TY - JOUR
T1 - The role of galactic winds on molecular gas emission from galaxy mergers
AU - Narayanan, Esika
AU - Cox, Thomas J.
AU - Kelly, Brandon
AU - Davé, Romeel
AU - Hernquist, Lars
AU - Matteo, Tiziana D.I.
AU - Hopkins, Philip F.
AU - Kulesa, Craig
AU - Robertson, Brant
AU - Walker, Christopher K.
PY - 2008/6/1
Y1 - 2008/6/1
N2 - Galactic winds from starbursts and active galactic nuclei (AGNs) are thought to play an important role in driving galaxies along the starburst-AGN sequence. Here, we assess the impact of these winds on the CO emission from galaxy mergers and, in particular, search for signatures of starburst and AGN-feedback-driven winds in the simulated CO morphologies and emission-line profiles. We do so by combining a three-dimensional non-LTE molecular line radiative transfer code with smoothed particle hydrodynamic (SPH) simulations of galaxy mergers that include prescriptions for star formation, black hole growth, a multiphase interstellar medium (ISM), and the winds associated with star formation and black hole growth. Our main results are (1) Galactic winds can drive outflows of masses ∼108-109 M ⊙ which may be imaged via CO emission-line mapping. (2) AGN-feedback-driven winds are able to drive detectable CO outflows for longer periods of time than starburst-driven winds owing to the greater amount of energy imparted to the ISM by AGN feedback compared to star formation. (3) Galactic winds can control the spatial extent of the CO emission in postmerger galaxies, and may serve as a physical motivation for the subkiloparsec scale CO emission radii observed in local advanced mergers. (4) Secondary emission peaks at velocities greater than the circular velocity are seen in the CO emission lines in all models, regardless of the associated wind model. In models with winds, however, these high-velocity peaks are seen to preferentially correspond to outfiowing gas entrained in winds, which is not the case in the model without winds. The high-velocity peaks seen in models without winds are typically confined to velocity offsets (from the systemic) ≤ 1.7 times the circular velocity, whereas the models with AGN-feedback-driven winds can drive high-velocity peaks to ∼2.5 times the circular velocity.
AB - Galactic winds from starbursts and active galactic nuclei (AGNs) are thought to play an important role in driving galaxies along the starburst-AGN sequence. Here, we assess the impact of these winds on the CO emission from galaxy mergers and, in particular, search for signatures of starburst and AGN-feedback-driven winds in the simulated CO morphologies and emission-line profiles. We do so by combining a three-dimensional non-LTE molecular line radiative transfer code with smoothed particle hydrodynamic (SPH) simulations of galaxy mergers that include prescriptions for star formation, black hole growth, a multiphase interstellar medium (ISM), and the winds associated with star formation and black hole growth. Our main results are (1) Galactic winds can drive outflows of masses ∼108-109 M ⊙ which may be imaged via CO emission-line mapping. (2) AGN-feedback-driven winds are able to drive detectable CO outflows for longer periods of time than starburst-driven winds owing to the greater amount of energy imparted to the ISM by AGN feedback compared to star formation. (3) Galactic winds can control the spatial extent of the CO emission in postmerger galaxies, and may serve as a physical motivation for the subkiloparsec scale CO emission radii observed in local advanced mergers. (4) Secondary emission peaks at velocities greater than the circular velocity are seen in the CO emission lines in all models, regardless of the associated wind model. In models with winds, however, these high-velocity peaks are seen to preferentially correspond to outfiowing gas entrained in winds, which is not the case in the model without winds. The high-velocity peaks seen in models without winds are typically confined to velocity offsets (from the systemic) ≤ 1.7 times the circular velocity, whereas the models with AGN-feedback-driven winds can drive high-velocity peaks to ∼2.5 times the circular velocity.
KW - Galaxies: active
KW - Galaxies: starburst
KW - ISM: jets and outflows
KW - Line: profiles
KW - Quasars: general
UR - http://www.scopus.com/inward/record.url?scp=46249098758&partnerID=8YFLogxK
U2 - 10.1086/533500
DO - 10.1086/533500
M3 - Article
AN - SCOPUS:46249098758
SN - 0067-0049
VL - 176
SP - 331
EP - 354
JO - Astrophysical Journal Supplement
JF - Astrophysical Journal Supplement
IS - 2
ER -