Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies

Gabriela Calistro Rivera, J. A. Hodge, Ian Smail, A. M. Swinbank, A. Weiss, J. L. Wardlow, F. Walter, M. Rybak, Chian Chou Chen, William Nielsen Brandt, K. Coppin, E. Da Cunha, H. Dannerbauer, T. R. Greve, A. Karim, K. K. Knudsen, E. Schinnerer, J. M. Simpson, B. Venemans, P. P.Van Der Werf

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ∼2-3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1-5 kpc (0.″1-0.″6). The velocity fields of our sources, traced by the 12CO(J =3-2) emission, are consistent with disk rotation to the first order, implying average dynamical masses of ∼3 1011 within two half-light radii. Through a Bayesian approach we investigate the uncertainties inherent to dynamically constraining total gas masses. We explore the covariance between the stellar mass-to-light ratio and CO-to-H2 conversion factor, α CO, finding values of for dark matter fractions of 15%. We show that the resolved spatial distribution of the gas and dust continuum can be uncorrelated to the stellar emission, challenging energy balance assumptions in global SED fitting. Through a stacking analysis of the resolved radial profiles of the CO(3-2), stellar, and dust continuum emission in SMG samples, we find that the cool molecular gas emission in these sources (radii ∼5-14 kpc) is clearly more extended than the rest-frame ∼250 μm dust continuum by a factor >2. We propose that assuming a constant dust-to-gas ratio, this apparent difference in sizes can be explained by temperature and optical depth gradients alone. Our results suggest that caution must be exercised when extrapolating morphological properties of dust continuum observations to conclusions about the molecular gas phase of the interstellar medium (ISM).

Original languageEnglish (US)
Article number56
JournalAstrophysical Journal
Volume863
Issue number1
DOIs
StatePublished - Aug 10 2018

Fingerprint

star formation
dust
galaxies
continuums
gas
molecular gases
gases
mass to light ratios
radii
stellar mass
stacking
optical thickness
optical depth
energy balance
dark matter
spatial distribution
velocity distribution
distribution
vapor phases
gradients

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Rivera, Gabriela Calistro ; Hodge, J. A. ; Smail, Ian ; Swinbank, A. M. ; Weiss, A. ; Wardlow, J. L. ; Walter, F. ; Rybak, M. ; Chen, Chian Chou ; Brandt, William Nielsen ; Coppin, K. ; Cunha, E. Da ; Dannerbauer, H. ; Greve, T. R. ; Karim, A. ; Knudsen, K. K. ; Schinnerer, E. ; Simpson, J. M. ; Venemans, B. ; Werf, P. P.Van Der. / Resolving the ISM at the Peak of Cosmic Star Formation with ALMA : The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies. In: Astrophysical Journal. 2018 ; Vol. 863, No. 1.
@article{dfd6f66c217b4e76b548749ca7383813,
title = "Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies",
abstract = "We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ∼2-3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1-5 kpc (0.″1-0.″6). The velocity fields of our sources, traced by the 12CO(J =3-2) emission, are consistent with disk rotation to the first order, implying average dynamical masses of ∼3 1011 within two half-light radii. Through a Bayesian approach we investigate the uncertainties inherent to dynamically constraining total gas masses. We explore the covariance between the stellar mass-to-light ratio and CO-to-H2 conversion factor, α CO, finding values of for dark matter fractions of 15{\%}. We show that the resolved spatial distribution of the gas and dust continuum can be uncorrelated to the stellar emission, challenging energy balance assumptions in global SED fitting. Through a stacking analysis of the resolved radial profiles of the CO(3-2), stellar, and dust continuum emission in SMG samples, we find that the cool molecular gas emission in these sources (radii ∼5-14 kpc) is clearly more extended than the rest-frame ∼250 μm dust continuum by a factor >2. We propose that assuming a constant dust-to-gas ratio, this apparent difference in sizes can be explained by temperature and optical depth gradients alone. Our results suggest that caution must be exercised when extrapolating morphological properties of dust continuum observations to conclusions about the molecular gas phase of the interstellar medium (ISM).",
author = "Rivera, {Gabriela Calistro} and Hodge, {J. A.} and Ian Smail and Swinbank, {A. M.} and A. Weiss and Wardlow, {J. L.} and F. Walter and M. Rybak and Chen, {Chian Chou} and Brandt, {William Nielsen} and K. Coppin and Cunha, {E. Da} and H. Dannerbauer and Greve, {T. R.} and A. Karim and Knudsen, {K. K.} and E. Schinnerer and Simpson, {J. M.} and B. Venemans and Werf, {P. P.Van Der}",
year = "2018",
month = "8",
day = "10",
doi = "10.3847/1538-4357/aacffa",
language = "English (US)",
volume = "863",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

Rivera, GC, Hodge, JA, Smail, I, Swinbank, AM, Weiss, A, Wardlow, JL, Walter, F, Rybak, M, Chen, CC, Brandt, WN, Coppin, K, Cunha, ED, Dannerbauer, H, Greve, TR, Karim, A, Knudsen, KK, Schinnerer, E, Simpson, JM, Venemans, B & Werf, PPVD 2018, 'Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies', Astrophysical Journal, vol. 863, no. 1, 56. https://doi.org/10.3847/1538-4357/aacffa

Resolving the ISM at the Peak of Cosmic Star Formation with ALMA : The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies. / Rivera, Gabriela Calistro; Hodge, J. A.; Smail, Ian; Swinbank, A. M.; Weiss, A.; Wardlow, J. L.; Walter, F.; Rybak, M.; Chen, Chian Chou; Brandt, William Nielsen; Coppin, K.; Cunha, E. Da; Dannerbauer, H.; Greve, T. R.; Karim, A.; Knudsen, K. K.; Schinnerer, E.; Simpson, J. M.; Venemans, B.; Werf, P. P.Van Der.

In: Astrophysical Journal, Vol. 863, No. 1, 56, 10.08.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Resolving the ISM at the Peak of Cosmic Star Formation with ALMA

T2 - The Distribution of CO and Dust Continuum in z ∼2.5 Submillimeter Galaxies

AU - Rivera, Gabriela Calistro

AU - Hodge, J. A.

AU - Smail, Ian

AU - Swinbank, A. M.

AU - Weiss, A.

AU - Wardlow, J. L.

AU - Walter, F.

AU - Rybak, M.

AU - Chen, Chian Chou

AU - Brandt, William Nielsen

AU - Coppin, K.

AU - Cunha, E. Da

AU - Dannerbauer, H.

AU - Greve, T. R.

AU - Karim, A.

AU - Knudsen, K. K.

AU - Schinnerer, E.

AU - Simpson, J. M.

AU - Venemans, B.

AU - Werf, P. P.Van Der

PY - 2018/8/10

Y1 - 2018/8/10

N2 - We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ∼2-3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1-5 kpc (0.″1-0.″6). The velocity fields of our sources, traced by the 12CO(J =3-2) emission, are consistent with disk rotation to the first order, implying average dynamical masses of ∼3 1011 within two half-light radii. Through a Bayesian approach we investigate the uncertainties inherent to dynamically constraining total gas masses. We explore the covariance between the stellar mass-to-light ratio and CO-to-H2 conversion factor, α CO, finding values of for dark matter fractions of 15%. We show that the resolved spatial distribution of the gas and dust continuum can be uncorrelated to the stellar emission, challenging energy balance assumptions in global SED fitting. Through a stacking analysis of the resolved radial profiles of the CO(3-2), stellar, and dust continuum emission in SMG samples, we find that the cool molecular gas emission in these sources (radii ∼5-14 kpc) is clearly more extended than the rest-frame ∼250 μm dust continuum by a factor >2. We propose that assuming a constant dust-to-gas ratio, this apparent difference in sizes can be explained by temperature and optical depth gradients alone. Our results suggest that caution must be exercised when extrapolating morphological properties of dust continuum observations to conclusions about the molecular gas phase of the interstellar medium (ISM).

AB - We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ∼2-3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1-5 kpc (0.″1-0.″6). The velocity fields of our sources, traced by the 12CO(J =3-2) emission, are consistent with disk rotation to the first order, implying average dynamical masses of ∼3 1011 within two half-light radii. Through a Bayesian approach we investigate the uncertainties inherent to dynamically constraining total gas masses. We explore the covariance between the stellar mass-to-light ratio and CO-to-H2 conversion factor, α CO, finding values of for dark matter fractions of 15%. We show that the resolved spatial distribution of the gas and dust continuum can be uncorrelated to the stellar emission, challenging energy balance assumptions in global SED fitting. Through a stacking analysis of the resolved radial profiles of the CO(3-2), stellar, and dust continuum emission in SMG samples, we find that the cool molecular gas emission in these sources (radii ∼5-14 kpc) is clearly more extended than the rest-frame ∼250 μm dust continuum by a factor >2. We propose that assuming a constant dust-to-gas ratio, this apparent difference in sizes can be explained by temperature and optical depth gradients alone. Our results suggest that caution must be exercised when extrapolating morphological properties of dust continuum observations to conclusions about the molecular gas phase of the interstellar medium (ISM).

UR - http://www.scopus.com/inward/record.url?scp=85051460801&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85051460801&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aacffa

DO - 10.3847/1538-4357/aacffa

M3 - Article

AN - SCOPUS:85051460801

VL - 863

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 56

ER -