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2MASS wide field extinction maps: II. The Ophiuchus and the Lupus cloud complexe
Marco Lombardi, Charles J. Lada, Joao Alves
We present an extinction map of a ~1,700 deg sq region that encloses the Ophiuchus, the Lupus, and the Pipe dark complexes using 42 million stars from the Two Micron All Sky Survey…
The dense ring in the Coalsack: the merging of two subsonic flows
J. M. Rathborne, C. J. Lada, W. Walsh +2
A recent high angular resolution extinction map toward the most opaque molecular globule, Globule 2, in the Coalsack Nebula revealed that it contains a strong central ring of dust…
New M dwarf debris disk candidates in NGC 2547
Jan Forbrich, Charles J. Lada, August A. Muench +1
With only six known examples, M-dwarf debris disks are rare, even though M dwarfs constitute the majority of stars in the Galaxy. After finding a new M dwarf debris disk in a shall…
Discovery of superthermal hydroxyl (OH) in the HH211 outflow
A. Tappe, C. J. Lada, J. H. Black +1
We present a 5-37 micron infrared spectrum obtained with the Spitzer Space Telescope toward the southeastern lobe of the young protostellar outflow HH211. The spectrum shows an ext…
Embedded Oscillating Starless Cores
Avery E. Broderick, Ramesh Narayan, Eric Keto +1
In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium pers…
Hipparcos distances of Ophiuchus and Lupus cloud complexes
M. Lombardi, C. Lada, J. Alves
We combine extinction maps from the Two Micron All Sky Survey (2MASS) with Hipparcos and Tycho parallaxes to obtain reliable and high-precision estimates of the distance to the Oph…
Spitzer imaging of the jet driving the NGC 2264 G outflow
Paula S. Teixeira, Carolyn McCoey, Michael Fich +1
We present new infrared imaging of the NGC 2264 G protostellar outflow region, obtained with the InfraRed Array Camera (IRAC) on-board the Spitzer Space Telescope. A jet in the red…
Oscillating Starless Cores: The Nonlinear Regime
Avery E. Broderick, Eric Keto, Charles J. Lada +1
In a previous paper, we modeled the oscillations of a thermally-supported (Bonnor-Ebert) sphere as non-radial, linear perturbations following a standard analysis developed for stel…
Using Chemistry to Unveil the Kinematics of Starless Cores: Complex Radial Motions in Barnard 68
Sébastien Maret, Edwin A. Bergin, Charles J. Lada
We present observations of 13CO, C18O, HCO+, H13CO+, DCO+ and N2H+ line emission towards the Barnard 68 starless core. The line profiles are interpreted using a chemical network co…
The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
Charles J. Lada, August A. Muench, Jill M. Rathborne +2
In this paper we present the results of a systematic investigation of an entire population of starless dust cores within a single molecular cloud. Analysis of extinction data shows…
The nature of the dense core population in the pipe nebula: core and cloud kinematics from C18O observations
August A. Muench, Charles J. Lada, Jill M. Rathborne +2
We present molecular-line observations of 94 dark cloud cores identified in the Pipe nebula through near-IR extinction mapping. Using the Arizona Radio Observatory 12m telescope, w…
The nature of the dense core population in the Pipe Nebula: A survey of NH3, CCS, and HC5N molecular line emission
J. M. Rathborne, C. J. Lada, A. A. Muench +2
Recent extinction studies of the Pipe Nebula (d=130 pc) reveal many cores spanning a range in mass from 0.2 to 20.4 Msun. These dense cores were identified via their high extinctio…
A dense micro-cluster of Class 0 protostars in NGC 2264 D-MM1
Paula S. Teixeira, Luis A. Zapata, Charles J. Lada
We present sensitive and high angular resolution (~1") 1.3 mm continuum observations of the dusty core D-MM1 in the Spokes cluster in NGC 2264 using the Submillimeter Array. A dens…
The Relationship between the Optical Depth of the 9.7 micron Silicate Absorption Feature and Infrared Differential Extinction in Dense Clouds
J. E. Chiar, K. Ennico, Y. J. Pendleton +8
We have examined the relationship between the optical depth of the 9.7 micron silicate absorption feature (tau_9.7) and the near-infrared color excess, E(J-Ks) in the Serpens, Taur…
The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
E. D. Aguti, C. J. Lada, E. A. Bergin +2
High resolution molecular line observations of CS, HCO+, C18O and N2H+ were obtained toward the starless globule FeSt 1-457 in order to investigate its kinematics and chemistry. Th…
The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
E. D. Aguti, C. J. Lada, E. A. Bergin +2
High resolution molecular line observations of CS, HCO+, C18O and N2H+ were obtained toward the starless globule FeSt 1-457 in order to investigate its kinematics and chemistry. Th…
The Infrared Extinction Law at Extreme Depth in a Dark Cloud Core
C. Román-Zúñiga, C. Lada, A. Muench +1
We combined sensitive near-infrared data obtained with ground-based imagers on the ESO NTT and VLT telescopes with space mid-infrared data acquired with the IRAC imager on the Spit…
A Spitzer census of the IC 348 nebula
August A. Muench, Charles J. Lada, K. L. Luhman +2
We present a Spitzer based census of the IC 348 nebula and embedded star cluster. Our Spitzer census supplemented by ground based spectra has added 42 class II T-Tauri sources to t…
The mass function of dense molecular cores and the origin of the IMF
J. Alves, M. Lombardi, C. Lada
Context: Stars form in the cold dense cores of interstellar molecular clouds and the detailed knowledge of the spectrum of masses of such cores is clearly a key for the understandi…
The Formation of Brown Dwarfs: Observations
Kevin L. Luhman, Viki Joergens, Charles Lada +3
We review the current state of observational work on the formation of brown dwarfs, focusing on their initial mass function, velocity and spatial distributions at birth, multiplici…
2MASS wide field extinction maps - I. The Pipe nebula
Marco Lombardi, Joao Alves, Charles J. Lada
We present a 8 deg x 6 deg, high resolution extinction map of the Pipe nebula using 4.5 million stars from the Two Micron All Sky Survey (2MASS) point source catalog. The use of NI…
The Thermal Structure of Gas in Pre-Stellar Cores: A Case Study of Barnard 68
E. A. Bergin, S. Maret, F. F. S. van der Tak +3
We present a direct comparison of a chemical/physical model to multitransitional observations of C18O and 13CO towards the Barnard 68 pre-stellar core. These observations provide a…
24-micron Detections of Disks around Very Low-mass Stars and Brown Dwarfs in IC 348: Grain Growth/Settling and Inner Holes?
James Muzerolle, Lucia Adame, Paola D'Alessio +11
We present observations of six late-type members of the young cluster IC 348 detected at 24 microns with the Multiband Imaging Photometer for Spitzer(MIPS). At least four of the ob…
Stellar Multiplicity and the IMF: Most Stars Are Single
Charles J. Lada
In this short communication I compare recent findings suggesting a low binary star fraction for late type stars with knowledge concerning the forms of the stellar initial and prese…