THE PdBI ARCSECOND WHIRLPOOL SURVEY (PAWS). I. A CLOUD-SCALE/MULTI-WAVELENGTH VIEW OF THE INTERSTELLAR MEDIUM IN A GRAND-DESIGN SPIRAL GALAXY

The Plateau de Bure Interferometer Arcsecond Whirlpool Survey has mapped the molecular gas in the central ∼9 kpc of M51 in its 12CO(1–0) line emission at a cloud-scale resolution of ∼40 pc using both IRAM telescopes. We utilize this data set to quantitatively characterize the relation of molecular gas (or CO emission) to other tracers of the interstellar medium, star formation, and stellar populations of varying ages. Using two-dimensional maps, a polar cross-correlation technique and pixel-by-pixel diagrams, we find: (1) that (as expected) the distribution of the molecular gas can be linked to different components of the gravitational potential; (2) evidence for a physical link between CO line emission and radio continuum that seems not to be caused by massive stars, but rather depends on the gas density; (3) a close spatial relation between polycyclic aromatic hydrocarbon (PAH) and molecular gas emission, but no predictive power of PAH emission for the molecular gas mass; (4) that the I − H color map is an excellent predictor of the distribution (and to a lesser degree, the brightness) of CO emission; and (5) that the impact of massive (UV-intense) young star-forming regions on the bulk of the molecular gas in central ∼9 kpc cannot be significant due to a complex spatial relation between molecular gas and star-forming regions that ranges from cospatial to spatially offset to absent. The last point, in particular, highlights the importance of galactic environment—and thus the underlying gravitational potential—for the distribution of molecular gas and star formation.

[1]  M. Sauvage,et al.  REGIONAL VARIATIONS IN THE DENSE GAS HEATING AND COOLING IN M51 FROM HERSCHEL FAR-INFRARED SPECTROSCOPY , 2013, 1308.3702.

[2]  J. Koda,et al.  GEOMETRIC OFFSETS ACROSS SPIRAL ARMS IN M51: NATURE OF GAS AND STAR FORMATION TRACERS , 2013, 1301.2601.

[3]  H. Rix,et al.  MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES , 2013, 1301.2328.

[4]  E. Pellegrini,et al.  THE CO-TO-H2 CONVERSION FACTOR AND DUST-TO-GAS RATIO ON KILOPARSEC SCALES IN NEARBY GALAXIES , 2012, 1212.1208.

[5]  S. Iguchi,et al.  GIANT MOLECULAR CLOUDS AND STAR FORMATION IN THE TIDAL MOLECULAR ARM OF NGC 4039 , 2012, 1211.0767.

[6]  G. Helou,et al.  THE STAR FORMATION IN RADIO SURVEY: GBT 33 GHz OBSERVATIONS OF NEARBY GALAXY NUCLEI AND EXTRANUCLEAR STAR-FORMING REGIONS , 2012, 1210.3360.

[7]  A. Leroy,et al.  GIANT MOLECULAR CLOUDS AND STAR FORMATION IN THE NON-GRAND DESIGN SPIRAL GALAXY NGC 6946 , 2012, 1208.5499.

[8]  M. Padovani,et al.  COSMIC-RAY AND X-RAY HEATING OF INTERSTELLAR CLOUDS AND PROTOPLANETARY DISKS , 2012, 1208.0523.

[9]  D. Calzetti,et al.  MODELING DUST AND STARLIGHT IN GALAXIES OBSERVED BY SPITZER AND HERSCHEL: NGC 628 AND NGC 6946 , 2012, 1207.4186.

[10]  D. Meier,et al.  SPATIALLY RESOLVED CHEMISTRY IN NEARBY GALAXIES. II. THE NUCLEAR BAR IN MAFFEI 2 , 2012, 1206.4098.

[11]  M. Sauvage,et al.  SPATIALLY RESOLVED STELLAR, DUST, AND GAS PROPERTIES OF THE POST-INTERACTING WHIRLPOOL GALAXY SYSTEM , 2012, 1206.2989.

[12]  B. Groves,et al.  The heating of dust by old stellar populations in the Bulge of M31 , 2012, 1206.2925.

[13]  A. Stilp,et al.  Implementing molecular hydrogen in hydrodynamic simulations of galaxy formation , 2012, 1205.5567.

[14]  H'elene Roussel,et al.  Scanamorphos: A Map-making Software for Herschel and Similar Scanning Bolometer Arrays , 2012, 1205.2576.

[15]  R. Klessen,et al.  How long does it take to form a molecular cloud , 2012, 1204.5570.

[16]  L. Ho,et al.  TWO POPULATIONS OF MOLECULAR CLOUDS IN THE ANTENNAE GALAXIES , 2012, 1203.1327.

[17]  B. Madore,et al.  ESTIMATING THE STAR FORMATION RATE AT 1 kpc SCALES IN NEARBY GALAXIES , 2012, 1202.2873.

[18]  B. Groves,et al.  RESOLVING THE FAR-IR LINE DEFICIT: PHOTOELECTRIC HEATING AND FAR-IR LINE COOLING IN NGC 1097 AND NGC 4559 , 2012, 1201.1016.

[19]  B. Groves,et al.  HERSCHEL FAR-INFRARED AND SUBMILLIMETER PHOTOMETRY FOR THE KINGFISH SAMPLE OF NEARBY GALAXIES , 2011, 1112.1093.

[20]  C. Kramer,et al.  Giant molecular clouds in the Local Group galaxy M 33 , 2011, 1111.4320.

[21]  B. Groves,et al.  KINGFISH—Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel: Survey Description and Image Atlas , 2011, 1111.4438.

[22]  E. Ostriker,et al.  A general model for the CO–H2 conversion factor in galaxies with applications to the star formation law , 2011, 1110.3791.

[23]  L. Ho,et al.  RECONSTRUCTING THE STELLAR MASS DISTRIBUTIONS OF GALAXIES USING S4G IRAC 3.6 AND 4.5 μm IMAGES. I. CORRECTING FOR CONTAMINATION BY POLYCYCLIC AROMATIC HYDROCARBONS, HOT DUST, AND INTERMEDIATE-AGE STARS , 2011, 1110.2683.

[24]  T. Sawada,et al.  RESOLVED MEASUREMENTS OF XCO IN NGC 6946 , 2011, 1109.6272.

[25]  M. Juvela,et al.  ON THE GAS TEMPERATURE OF MOLECULAR CLOUD CORES , 2011, 1108.1345.

[26]  A. Hirota,et al.  GIANT MOLECULAR CLOUDS IN THE SPIRAL ARM OF IC 342 , 2011, 1106.5744.

[27]  K. Sandstrom,et al.  Common-Resolution Convolution Kernels for Space- and Ground-Based Telescopes , 2011, 1106.5065.

[28]  H. Rix,et al.  OBSERVATIONAL EVIDENCE AGAINST LONG-LIVED SPIRAL ARMS IN GALAXIES , 2011, 1105.5141.

[29]  D. Calzetti,et al.  CALIBRATING EXTINCTION-FREE STAR FORMATION RATE DIAGNOSTICS WITH 33 GHz FREE–FREE EMISSION IN NGC 6946 , 2011, 1105.4877.

[30]  C. Kramer,et al.  A MOLECULAR STAR FORMATION LAW IN THE ATOMIC-GAS-DOMINATED REGIME IN NEARBY GALAXIES , 2011, 1105.4605.

[31]  R. Klessen,et al.  Modelling CO emission – II. The physical characteristics that determine the X factor in Galactic molecular clouds , 2011, 1104.3695.

[32]  N. Hwang,et al.  H ii REGION LUMINOSITY FUNCTION OF THE INTERACTING GALAXY M51 , 2011, 1104.3669.

[33]  The University of Toledo,et al.  USING Hα MORPHOLOGY AND SURFACE BRIGHTNESS FLUCTUATIONS TO AGE-DATE STAR CLUSTERS IN M83 , 2011, 1103.4026.

[34]  J. Beckman,et al.  PROPERTIES OF THE H ii REGION POPULATIONS OF M51 AND NGC 4449 FROM Hα IMAGES WITH THE ADVANCED CAMERA FOR SURVEYS ON THE HUBBLE SPACE TELESCOPE , 2011 .

[35]  E. Brinks,et al.  A CONSTANT MOLECULAR GAS DEPLETION TIME IN NEARBY DISK GALAXIES , 2011, 1102.1720.

[36]  Laboratoire d'Astrophysique de Marseille,et al.  RADIAL DISTRIBUTION OF STARS, GAS, AND DUST IN SINGS GALAXIES. III. MODELING THE EVOLUTION OF THE STELLAR COMPONENT IN GALAXY DISKS , 2011, 1102.1724.

[37]  Angela V. Olinto,et al.  The Astrophysics of Ultrahigh-Energy Cosmic Rays , 2011, 1101.4256.

[38]  D. Calzetti,et al.  NEW CONSTRAINTS ON MASS-DEPENDENT DISRUPTION OF STAR CLUSTERS IN M51 , 2011, 1101.2869.

[39]  O. Ilbert,et al.  THE STAR FORMATION HISTORY OF MASS-SELECTED GALAXIES IN THE COSMOS FIELD , 2010, 1011.6370.

[40]  E. Murphy,et al.  THE LOCAL RADIO–IR RELATION IN M51 , 2010, 1012.0212.

[41]  R. Meijerink,et al.  Star formation in extreme environments: the effects of cosmic rays and mechanical heating , 2010, 1010.0788.

[42]  Fabian Walter,et al.  ARM AND INTERARM STAR FORMATION IN SPIRAL GALAXIES , 2010, 1010.0678.

[43]  D. Benford,et al.  A 158 μm [C ii] LINE SURVEY OF GALAXIES AT z ∼ 1–2: AN INDICATOR OF STAR FORMATION IN THE EARLY UNIVERSE , 2010, 1009.4216.

[44]  A. Leroy,et al.  THE SCALE DEPENDENCE OF THE MOLECULAR GAS DEPLETION TIME IN M33 , 2010, 1009.1651.

[45]  N. Evans,et al.  THE STAR FORMATION RATE AND GAS SURFACE DENSITY RELATION IN THE MILKY WAY: IMPLICATIONS FOR EXTRAGALACTIC STUDIES , 2010, 1009.1621.

[46]  P. Papadopoulos.  A COSMIC-RAY-DOMINATED INTERSTELLAR MEDIUM IN ULTRA LUMINOUS INFRARED GALAXIES: NEW INITIAL CONDITIONS FOR STAR FORMATION , 2010, 1009.1134.

[47]  B. Madore,et al.  TIGHTLY CORRELATED H i AND FUV EMISSION IN THE OUTSKIRTS OF M83 , 2010, 1007.4550.

[48]  Jr.,et al.  OPTICAL SPECTROSCOPY AND NEBULAR OXYGEN ABUNDANCES OF THE SPITZER/SINGS GALAXIES , 2010, 1007.4547.

[49]  A. Weiss,et al.  MULTI-TRANSITION STUDY OF M51'S MOLECULAR GAS SPIRAL ARMS , 2010, 1007.0692.

[50]  D. Fisher,et al.  BULGES OF NEARBY GALAXIES WITH SPITZER: SCALING RELATIONS IN PSEUDOBULGES AND CLASSICAL BULGES , 2010, 1004.5393.

[51]  A. Bolatto,et al.  THE SPITZER SURVEY OF THE SMALL MAGELLANIC CLOUD (S3MC): INSIGHTS INTO THE LIFE CYCLE OF POLYCYCLIC AROMATIC HYDROCARBONS , 2010, 1003.4516.

[52]  F. Liu,et al.  THE RADIO CONTINUUM, FAR-INFRARED EMISSION, AND DENSE MOLECULAR GAS IN GALAXIES , 2010, 1003.3505.

[53]  S. Glover,et al.  On the relationship between molecular hydrogen and carbon monoxide abundances in molecular clouds , 2010, 1003.1340.

[54]  C. Horellou,et al.  Magnetic fields and spiral arms in the galaxy M51 , 2010, 1001.5230.

[55]  Laboratoire d'Astrophysique de Marseille,et al.  RADIAL DISTRIBUTION OF STARS, GAS, AND DUST IN SINGS GALAXIES. II. DERIVED DUST PROPERTIES , 2009, 0909.2658.

[56]  R. Klessen,et al.  Modelling CO formation in the turbulent interstellar medium , 2009, 0907.4081.

[57]  S. L. Scott,et al.  DYNAMICALLY DRIVEN EVOLUTION OF THE INTERSTELLAR MEDIUM IN M51 , 2009, 0907.1656.

[58]  E. Dishoeck,et al.  The photodissociation and chemistry of CO isotopologues: applications to interstellar clouds and circumstellar disks , 2009, 0906.3699.

[59]  R. Scheepmaker,et al.  The spatial distribution of star and cluster formation in M 51 , 2008, 0812.1417.

[60]  Nickolay Y. Gnedin,et al.  MODELING MOLECULAR HYDROGEN AND STAR FORMATION IN COSMOLOGICAL SIMULATIONS , 2008, 0810.4148.

[61]  E. Brinks,et al.  THINGS: THE H i NEARBY GALAXY SURVEY , 2008, 0810.2125.

[62]  Alexander G. G. M. Tielens,et al.  Interstellar Polycyclic Aromatic Hydrocarbon Molecules , 2008 .

[63]  M. Merrifield,et al.  Radial Dependence of the Pattern Speed of M51 , 2008, 0807.1902.

[64]  R. Ekers,et al.  Interpretation of radio continuum and molecular line observations of Sgr B2: free-free and synchrotron emission, and implications for cosmic rays , 2008, 0807.0127.

[65]  R. Scheepmaker,et al.  ACS imaging of star clusters in M 51 : II. The luminosity function and mass function across the disk , 2008, 0806.3752.

[66]  Adam K. Leroy,et al.  The Resolved Properties of Extragalactic Giant Molecular Clouds , 2008, Proceedings of the International Astronomical Union.

[67]  G. Helou,et al.  A Compendium of Far-Infrared Line and Continuum Emission for 227 Galaxies Observed by the Infrared Space Observatory , 2008, 0805.2930.

[68]  A. Tielens,et al.  Chemical Rates on Small Grains and PAHs: C+ Recombination and H2 Formation , 2008, 0803.0138.

[69]  A. Goodman,et al.  CO Isotopologues in the Perseus Molecular Cloud Complex: the X-factor and Regional Variations , 2008, 0802.0708.

[70]  N. Hwang,et al.  A CATALOG OF BRIGHT STAR CLUSTERS IN THE INTERACTING GALAXY M51 , 2007, 0712.1420.

[71]  K. Sheth,et al.  Warm Molecular Gas in M51: Mapping the Excitation Temperature and Mass of H2 with the Spitzer Infrared Spectrograph , 2007, 0712.0022.

[72]  B. Robertson,et al.  Molecular Hydrogen and Global Star Formation Relations in Galaxies , 2007, 0710.2102.

[73]  K. Menten,et al.  High-resolution radio continuum survey of M 33 - II. Thermal and nonthermal emission , 2007, 0708.2484.

[74]  E. Ostriker,et al.  Kinematics of Spiral-Arm Streaming in M51 , 2007, 0705.3240.

[75]  N. Bastian,et al.  ACS imaging of star clusters in M 51. I. Identification and radius distribution , 2007, 0704.3604.

[76]  S. Muller,et al.  Jet-disturbed molecular gas near the Seyfert 2 nucleus in M 51 , 2007, 0704.0947.

[77]  E. Schinnerer,et al.  A Study of Compact Radio Sources in Nearby Face-on Spiral Galaxies. II. Multiwavelength Analyses of Sources in M51 , 2007, astro-ph/0702310.

[78]  Y. Hagiwara.  Low-Luminosity Extragalactic Water Masers toward M82, M51, and NGC 4051 , 2007, astro-ph/0702678.

[79]  G. Ferland,et al.  A photon dominated region code comparison study , 2007, astro-ph/0702231.

[80]  P. Hennebelle,et al.  On the structure of the turbulent interstellar atomic hydrogen. I- Physical characteristics Influence and nature of turbulence in a thermally bistable flow , 2006, astro-ph/0612778.

[81]  D. Calzetti,et al.  The Mid-Infrared Spectrum of Star-forming Galaxies: Global Properties of Polycyclic Aromatic Hydrocarbon Emission , 2006, astro-ph/0610913.

[82]  C. Horellou,et al.  Analysis of spiral arms using anisotropic wavelets: gas, dust and magnetic fields in M51 , 2006, astro-ph/0609787.

[83]  C. Kramer,et al.  A complete 12CO 2-1 map of M51 with HERA: I. Radial averages of CO, HI, and radio continuum , 2006, astro-ph/0609670.

[84]  R. Meijerink,et al.  Irradiated ISM: Discriminating between Cosmic Rays and X-Rays , 2006, astro-ph/0609184.

[85]  B. Draine,et al.  Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era , 2006, astro-ph/0608003.

[86]  R. Indebetouw,et al.  Structure Generation by Irradiation: What Can GLIMPSE Teach Us about the ISM Structure? , 2006, astro-ph/0607318.

[87]  E. Ostriker,et al.  A Hubble Space Telescope Archival Survey of Feathers in Spiral Galaxies , 2006, astro-ph/0606761.

[88]  Todd A. Thompson,et al.  The Starburst Contribution to the Extragalactic γ-Ray Background , 2006, astro-ph/0606665.

[89]  M. Lombardi,et al.  2MASS wide field extinction maps. I. The Pipe nebula , 2006, astro-ph/0606670.

[90]  R. Paladino,et al.  Thermal and non-thermal components of the interstellar medium at sub-kiloparsec scales in galaxies , 2006, astro-ph/0606480.

[91]  F. Combes,et al.  SF2A-2004: Semaine de l'Astrophysique Francaise , 2005 .

[92]  SRON,et al.  Hierarchical Star Formation in M51: Star/Cluster Complexes , 2005, astro-ph/0508110.

[93]  L. Kewley,et al.  Star Formation in NGC 5194 (M51a): The Panchromatic View from GALEX to Spitzer , 2005, astro-ph/0507427.

[94]  Linda J. Smith,et al.  SPITZER SURVEY OF THE LARGE MAGELLANIC CLOUD, SURVEYING THE AGENTS OF A GALAXY'S EVOLUTION (SAGE). IV. DUST PROPERTIES IN THE INTERSTELLAR MEDIUM , 2005, Proceedings of the International Astronomical Union.

[95]  R. Ekers,et al.  The molecular connection to the FIR-radio continuum correlation in galaxies , 2005, astro-ph/0503565.

[96]  A. Szalay,et al.  The On-Orbit Performance of the Galaxy Evolution Explorer , 2004, astro-ph/0411310.

[97]  D. Meier,et al.  Spatially Resolved Chemistry in Nearby Galaxies. I. The Center of IC 342 , 2004, astro-ph/0410039.

[98]  F. Bresolin,et al.  Abundances of Metal-rich H II Regions in M51 , 2004, astro-ph/0407065.

[99]  E. Rosolowsky,et al.  Giant Molecular Clouds in M33. II. High-Resolution Observations , 2003, astro-ph/0307322.

[100]  R. Gutermuth,et al.  Star Formation and Asymmetry in the Spiral Arms of M51: Variable Star Formation Caused by More than One Spiral Density Wave , 2003, astro-ph/0306420.

[101]  M. Dopita,et al.  The Radio–FIR Correlation: Is MHD Turbulence the Cause? , 2003, Publications of the Astronomical Society of Australia.

[102]  A. Bolatto,et al.  CO (J = 7→6) Observations of NGC 253: Cosmic-Ray-heated Warm Molecular Gas , 2002, astro-ph/0212271.

[103]  L. Blitz,et al.  The BIMA Survey of Nearby Galaxies (BIMA SONG). II. The CO Data , 2002, astro-ph/0304294.

[104]  K. Sheth,et al.  Molecular Gas and Star Formation in Bars of Nearby Spiral Galaxies , 2002, astro-ph/0208018.

[105]  R. Ciardullo,et al.  Planetary Nebulae as Standard Candles. XII. Connecting the Population I and Population II Distance Scales , 2002, astro-ph/0206177.

[106]  L. Gregorini,et al.  Radio continuum and CO emission in star-forming galaxies. , 2002, astro-ph/0201478.

[107]  R. Kirshner,et al.  Ongoing Massive Star Formation in the Bulge of M51 , 2001, astro-ph/0112034.

[108]  Jr.,et al.  SINGS: The SIRTF Nearby Galaxies Survey , 2001, astro-ph/0305437.

[109]  P. Goldsmith.  Molecular Depletion and Thermal Balance in Dark Cloud Cores , 2000 .

[110]  A. Weiss,et al.  The Effect of Violent Star Formation on the State of the Molecular Gas in M 82 , 2000, astro-ph/0010541.

[111]  E. Ostriker,et al.  Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models , 2000, astro-ph/0008454.

[112]  H. Ford,et al.  Molecular Gas in the Inner 100 Parsecs of M51 , 1998 .

[113]  Jr.,et al.  The Global Schmidt law in star forming galaxies , 1997, astro-ph/9712213.

[114]  C. Wilson,et al.  The Density and Temperature of Molecular Clouds in M33 , 1997, astro-ph/9701245.

[115]  L. Blitz,et al.  Synthesis Imaging of Dense Gas in Nearby Galaxies , 1996, astro-ph/9610103.

[116]  A. Tielens,et al.  X-Ray--irradiated Molecular Gas. I. Physical Processes and General Results , 1996 .

[117]  K. Kohno,et al.  Aperture Synthesis CO and HCN Observations of M51: Dense Molecular Disk around a Low-Luminosity Active Galactic Nucleus , 1996 .

[118]  L. Gentet,et al.  Scale Lengths in Disk Surface Brightness as probes of Dust Extinction in 3 Spiral Galaxies: M 51, NGC 3631 and M 100 , 1996, astro-ph/9602098.

[119]  G. Melnick,et al.  Thermal Balance in Dense Molecular Clouds: Radiative Cooling Rates and Emission-Line Luminosities , 1995 .

[120]  A. Tielens,et al.  THE PHOTOELECTRIC HEATING MECHANISM FOR VERY SMALL GRAPHITIC GRAINS AND POLYCYCLIC AROMATIC HYDROCARBONS , 1994 .

[121]  Marcia J. Rieke,et al.  Tracing the stellar mass in M51 , 1993 .

[122]  T. Heckman,et al.  Cosmic-Ray--dominated Dense Molecular Gas in Normal and Starburst Galaxies , 1993 .

[123]  R. Gruendl,et al.  H-ALPHA FABRY-PEROT OBSERVATIONS OF THE DENSITY WAVE PATTERN IN M51 , 1993 .

[124]  R. Allen.  A surface brightness correlation between carbon monoxide and nonthermal radio continuum emission in the galaxy , 1992 .

[125]  P. Crane,et al.  THE RADIO JET IN M51 , 1992 .

[126]  R. Allen,et al.  The relationship between the carbon monoxide intensity and the radio continuum emission in spiral galaxies , 1991 .

[127]  A. Poglitsch,et al.  The 158 micron forbidden C II line - A measure of global star formation activity in galaxies , 1991 .

[128]  N. Devereux,et al.  THE GAS DUST RATIO IN SPIRAL GALAXIES , 1990 .

[129]  N. Evans,et al.  Molecular clouds in the outer Galaxy. IV, Studies of star formation , 1990 .

[130]  R. Kennicutt.  The Star Formation Law in Galactic Disks , 1989 .

[131]  P. Seiden,et al.  Spiral arm amplitude variations and pattern speeds in the grand design galaxies M51, M81, and M100 , 1989 .

[132]  E. Parker,et al.  Intermittent Behavior of Galactic Dynamo Activities , 1989 .

[133]  A. Sternberg,et al.  The infrared response of molecular hydrogen gas to ultraviolet radiation: high-density regions , 1989 .

[134]  P. Solomon,et al.  Star formation rates and the far-infrared luminosity of Galactic molecular clouds , 1988 .

[135]  J. Black,et al.  The photodissociation and chemistry of interstellar CO , 1988 .

[136]  S. R. Kulkarni,et al.  Star formation in giant molecular associations synchronized by a spiral density wave , 1988, Nature.

[137]  R. Tilanus,et al.  Spiral structure of M51 - thermal and nonthermal emission , 1988 .

[138]  Philip R. Maloney,et al.  I(CO)/N(H2) conversions and molecular gas abundances in spiral and irregular galaxies , 1988 .

[139]  A. R. Rivolo,et al.  Mass, luminosity, and line width relations of Galactic molecular clouds , 1987 .

[140]  F. Schloerb,et al.  Carbon monoxide as an extragalactic mass tracer , 1986 .

[141]  A. Tielens,et al.  Photodissociation regions. I - Basic model. II - A model for the Orion photodissociation region , 1985 .

[142]  N. Scoville,et al.  Giant molecular clouds in the galaxy. II. Characteristics of discrete features , 1985 .

[143]  F. Israel,et al.  Correlation of CO line and radio continuum emission in nearby galaxies and the efficiency of OB star formation , 1984 .

[144]  R. McCray,et al.  X-ray sources in molecular clouds , 1983 .

[145]  D. Hollenbach,et al.  The gas-grain interaction in the interstellar medium - Thermal accommodation and trapping , 1983 .

[146]  D. Hollenbach,et al.  Molecule formation and infrared emission in fast interstellar shocks. I Physical processes , 1979 .

[147]  B. Savage,et al.  A survey of interstellar H I from L-alpha absorption measurements. II , 1978 .

[148]  R. Dickman,et al.  The ratio of carbon monoxide to molecular hydrogen in interstellar dark clouds , 1978 .

[149]  P. Goldsmith,et al.  Molecular cooling and thermal balance of dense interstellar clouds , 1978 .

[150]  R. L. Brown,et al.  Energetic secondary electrons and the nonthermal galactic radio background - A probe of the magnetic field in interstellar clouds , 1978 .

[151]  B. Draine.  Photoelectric heating of interstellar gas , 1978 .

[152]  Lee J. Rickard,et al.  Extragalactic carbon monoxide , 1977 .

[153]  R. Tully.  The kinematics and dynamics of M51. III. The spiral structure , 1974 .

[154]  J. Simon,et al.  Accepted for publication in The Astrophysical Journal Preprint typeset using L ATEX style emulateapj v. 6/22/04 THE MOLECULAR ISM OF DWARF GALAXIES ON KILOPARSEC SCALES: A NEW SURVEY FOR CO IN NORTHERN, IRAS-DETECTED DWARF GALAXIES , 2005 .

[155]  (DOI: will be inserted by hand later) Molecular gas in the Andromeda galaxy , 2003 .

[156]  U. Maryland,et al.  Accepted for publication in The Astrophysical Journal. Preprint typeset using L ATEX style emulateapj v. 21/08/00 A CHANDRA OBSERVATION OF M51: ACTIVE NUCLEUS AND NUCLEAR OUTFLOWS , 2001 .

[157]  E. Vishniac,et al.  ApJ accepted Preprint typeset using LATEX style emulateapj v. 04/03/99 THE GENERATION OF MAGNETIC FIELDS THROUGH DRIVEN TURBULENCE , 2000 .

[158]  Yong-Seo Park,et al.  ApJ, in press , 1999 .

[159]  G. A. Croes,et al.  FITS++: An Object-Oriented Set of C++ Classes to Support FITS , 1997 .

[160]  D. Zaritsky,et al.  Inner spiral structure of the galaxy M51 , 1993, Nature.

[161]  James J. Condon,et al.  Radio Emission from Normal Galaxies , 1992 .

[162]  P. Roelfsema,et al.  Astronomical Data Analysis Software and Systems I , 1992 .

[163]  N. Scoville,et al.  Molecular gas in galaxies , 1991 .

[164]  H. Bloemen.  Diffuse Galactic gamma-ray emission , 1989 .

[165]  H. Ford,et al.  High-Resolution Radio Observations of the Bubbles and Jets in the Center of M51 , 1987 .

[166]  J. Black,et al.  Interstellar H$sub 2$: The population of excited rotational states and the infrared response to ultraviolet radiation , 1976 .

[167]  Edwin E. Salpeter,et al.  Surface recombination of hydrogen molecules , 1971 .

[168]  Accepted to The Astrophysical Journal. Preprint typeset using L ATEX style emulateapj v. 10/09/06 A NEAR-INFRARED STUDY OF 2MASS BARS IN LOCAL GALAXIES: AN ANCHOR FOR HIGH REDSHIFT STUDIES , 2022 .

[169]  A. Leroy,et al.  Accepted for publication in The Astronomical Journal Preprint typeset using L ATEX style emulateapj v. 08/13/06 THE STAR FORMATION EFFICIENCY IN NEARBY GALAXIES: MEASURING WHERE GAS FORMS STARS EFFECTIVELY , 2022 .

[170]  Accepted for Publication in The Astronomical Journal Preprint typeset using L ATEX style emulateapj v. 10/09/06 THE STAR FORMATION LAW IN NEARBY GALAXIES ON SUB-KPC SCALES , 2022 .