Welcome to the Star Formation Group
We study the physics of star formation from 100AU to 100kpc scales, from individual protostars in our Galaxy to compact groups of galaxies. This breadth allows us to ground galaxy-scale star formation in an understanding of the microphysics, and place individual nearby regions in broader environmental context. We use observational techniques from X-ray to centimeter, with particular recent focus on infrared and (sub)millimeter, as well as radiative transfer and other numerical models.
HERACLES Adam Leroy PI'd the HERACLES survey, now available through their online database. The HERA CO-Line Extragalactic Survey (HERACLES) is a Large Program that used the IRAM 30-m telescope to map CO emission from 48 nearby galaxies. As the second most common molecule, CO acts as our primary tracer of molecular, star-forming gas in galaxies. HERACLES covered a wide area in each target (out to the 'optical' radius, r25) with good sensitivity. We built HERACLES to complement THINGS, SINGS, and associated surveys. As a result we know the detailed distributions of atomic gas (HI), infrared, ultraviolet, and optical light across each galaxy. This makes HERACLES a powerful data set to study the formation of stars from molecular gas, the assembly of molecular clouds out of atomic gas, the distribution of matter (dark, light, stellar, and gaseous) in galaxies, and the dynamics and structure of the interstellar medium.
Faculty and Staff
- Crystal Brogan (NRAO)
- Jennifer Donovan Meyer (NRAO)
- Todd Hunter (NRAO)
- Remy Indebetow
- Kelsey Johnson
- Duncan Christie
- Amanda Heiderman
- Amandy Kepley
- Sabrina Stierwalt
- Loreto Barcos
- Lauren Bittle
- Cheoljong Lee
- Sandy Liss
- Kim Sokal
- Natalie Butterfield
- Rosie Chen
- Ian Czekala
- William Dirienzo
- Meredith Drosback
- Amanda Kepley
- Adam Leroy
- Paul Martini
- Josh Nunn
- Karin Öberg
- George Privon
- Amy Reines
- Scott Schnee
- Lisa May Walker
- David Whelan
- Catherine Zucker
Star Formation at UVa+NRAO Projects
Compact Groups of Galaxies
How does star formation and gas processing proceed in these systems reminiscent of the era of galaxy formation? What is the relationship between the evolutionary states of compact groups and their gas and dust content? How is this affected by multiple simultaneous interactions?
- Walker et al. (2013) "The Optical Green Valley versus Mid-infrared Canyon in Compact Groups"
- Walker et al. (2012) "Examining the Role of Environment in a Comprehensive Sample of Compact Groups"
- Walker et al. (2010) "Mid-Infrared Evidence for Accelerated Evolution in Compact Group Galaxies"
- Gallagher, Johnson, et al. (2008) "The Revealing Dust: Mid-Infrared Activity in Hickson Compact Group Galaxy Nuclei"
- Johnson et al. (2007) "The Infrared Properties of Hickson Compact Groups"
Nearby Luminous and Ultra-Luminous Infrared Galaxies
What is the true distribution of the star formation in these compact, dust embedded systems? How does the range in star formation rate surface density compare with theoretical estimates? Are these systems producing stars at the Eddington limit set by radiation pressure on dust? What is powering their luminosities?
- Barcos-Muñoz, L. et al. (2015) "High Resolution Radio Continuum Measurements of the Nuclear Disks of Arp 220"
- Stiwerwalt, S. et al. (2014) "Mid-IR Properties of LIRGs II: Probing the Dust and Gas Physics of the GOALS Sample"
- Stierwalt, S. et al. (2013) "Mid-Infrared Properties of Nearby Luminous Infrared Galaxies. I. Spitzer infrared Spectrograph Spectra for the GOALS Sample
- Privon, G., C. et al. (2013) "Dynamical Modeling of Galaxy Mergers Using Identikit"
- Leroy, A. et al. (2011) "Complex Radio Spectral Energy Distributions in Luminous and Ultraluminous Infrared Galaxies"
Resolved Nearby Galaxies
What determines the rates and history of star formation within galaxies? What are the extremes of this process, for example star formation at low metallicity (SMC) and tidal features (Magellanic Bridge)?
SAGE and HERITAGE projects
- Andrews & Martini (2012) "The Mass-Metallicity Relation with the Direct Method on Stacked Spectra of SDSS Galaxies"
- Leroy et al. (2012) "Estimating the Star Formation Rate at 1 kpc Scales in nearby Galaxies"
- Schruba, Leroy et al. (2012) "Low CO Luminosities in Dwarf Galaxies"
- Bolatto, Leroy et al. (2011) "The State of the Gas and the Relation between Gas and Star Formation at Low Metallicity: The Small Magellanic Cloud"
- Leroy et al. (2011) "The CO-to-H2 Conversion Factor from Infrared Dust Emission across the Local Group"
- Kepley et al. (2011) "Unveiling Extragalactic Star Formation Using Radio Recombination Lines: An Expanded Very Large Array Pilot Study with NGC 253"
- Lawton et al. (2010) "Spitzer Analysis of H II Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator"
- Bigiel, Leroy et al.(2010) "Tightly Correlated H I and FUV Emission in the Outskirts of M83"
Super Star Clusters
What causes this most extreme mode of star formation? Where and what kinds of super star clusters form, what are their properties at the earliest evolutionary stages? What special physics arises in and near these extraordinary objects?
- Whelan et al. (2011) "The Infrared Properties of Super Star Clusters: Predictions from Three-Dimensional Radiative Transfer Models."
- Brogan, Johnson, & Darling (2010) "Water Masers associated with Star Formation in the Antennae Galaxies"
- Reines et al. (2010) "The Importance of Nebular Continuum and Line Emission in Observations of Young Massive Star Clusters"
- Johnson, Hunt, & Reines (2009) "Probing Star Formation at Low Metallicity: The Radio Emission of Super Star Clusters in SBS 0335-052"
What effects do protostars and young massive stars have on their circumstellar and interstellar medium? How does this regular further star formation? We are studying this in the Magellanic System on region and galaxy scales using primarily Spitzer and Herschel, and in Galactic molecular clouds with our own near-IR narrow-band survey of outflow activity. Under what circumstances does feedback lead to triggered star formation?
- Indebetouw et al. (2014) "Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA"
- Dirienzo et al. (2012) "Testing Triggered Star Formation in Six H II Regions"
- Desai et al. (2010) "Supernova Remnants and Star Formation in the Large Magellanic Cloud"
- Hony et al. (2010) "The Herschel revolution: Unveiling the morphology of the high-mass star-formation sites N44 and N63 in the LMC"
- Meixner et al. (2010) "HERschel Inventory of The Agents of Galaxy Evolution (HERITAGE): The Large Magellanic Cloud dust"
- Kemper et al. (2010) "The SAGE-Spec Spitzer Legacy Program: The Life Cycle of Dust and Gas in the Large Magellanic Cloud"
- Indebetouw et al. (2009) "Physical Conditions in the Ionized Gas of 30 Doradus"
- Rubin et al. (2009) "A spatially resolved study of photoelectric heating and [C II] cooling in the LMC. Comparison with dust emission as seen by SAGE"
Formation of Massive Stars
Massive stars drive the evolution of the visible universe - does their formation require different physics from solar-mass stars? What can we learn from the highest-resolution observations of young massive stars, and from their outflows and environments in our Galaxy and the Magellanic System? What properties of a molecular cloud lead to massive star and cluster formation, contrasted with distributed low-mass star formation?
- Chen et al. (2010) "Spitzer View of Young Massive Stars in the Large Magellanic Cloud H II Complexes. II. N 159"
- Romita et al. (2010) "Young Stellar Objects in the Large Magellanic Cloud Star-forming Region N206"
- Sewiło, Indebetouw et al. (2010) "The youngest massive protostars in the Large Magellanic Cloud"
- Fleener et al. (2010) "Massive Star Formation in NGC 2074"
- Vaidya et al. (2009) "A Hubble Space Telescope View of the Interstellar Environments of Young Stellar Objects in the Large Magellanic Cloud"
- Oliveira et al. (2009) "Ice Chemistry in Embedded Young Stellar Objects in the Large Magellanic Cloud"
- Brogan et al. (2009) "Digging Into NGC 6334 I(N): Multiwavelength Imaging of a Massive Protostellar Cluster"
- Seale et al. (2009) "The Evolution Of Massive Young Stellar Objects in the Large Magellanic Cloud. I. Identification and Spectral Classification"
- Povich et al. (2009) "The Extended Environment of M17: A Star Formation History"
- Chen et al. (2009) "Spitzer View of Young Massive Stars in the Large Magellanic Cloud H II Complex N 44"
- Churchwell et al. (2009) "The Spitzer/GLIMPSE Surveys: A New View of the Milky Way"
Chemistry and Star Formation
The formation of stars (and planets) is accompanied by molecular formation and destruction. The chemistry of many species depends strongly on the local environment and how this environment has evolved. Molecular spectra can therefore be used as probes of key aspects of star formation, from cloud formation and evolution, through cloud collapse and the protostellar phase, to the formation of accretion disks and planetary systems. Within the star formation group we observe molecular spectral features from IR to mm wavelengths to explore the evolution of molecular clouds and protostars, and to test our chemical understanding of proposed molecular probes.
- Öberg et al. (2011) "The Spitzer Ice Legacy: Ice Evolution from Cores to Protostars"
- Öberg et al. (2011) "Complex Molecules toward Low-mass Protostars: The Serpens Core"
- Öberg et al. (2010) "A Cold Complex Chemistry Toward the Low-mass Protostar B1-b: Evidence for Complex Molecule Production in Ices"
- Schnee et al. (2012) "An Observed Lack of Substructure in Starless Cores. II. Super-Jeans Cores"
- Schnee et al. (2012) "How Starless are Starless Cores?"
- Schnee et al. (2010) "An Observed Lack of Substructure in Starless Cores"
- Schnee et al. (2010) "The Dust Emissivity Spectral Index in the Starless Core TMC-1C"