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The Pipe Nebula is a massive, nearby dark molecular cloud with a low star-formation efficiency which makes it a good laboratory to study the very early stages of the star formation process. The Pipe Nebula is largely filamentary, and…

The Pipe nebula is a massive, nearby, filamentary dark molecular cloud with a low star-formation efficiency threaded by a uniform magnetic field perpendicular to its main axis. It harbors more than a hundred, mostly quiescent, very…

We aim to investigate the polarization properties of a starless core in a very early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to…

Solar and Stellar Astrophysics · Physics 2014-09-17 Felipe Alves , Pau Frau , Josep M. Girart , Gabriel A. P. Franco , Fábio P. Santos , Helmut Wiesemeyer

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 cores to be dense objects characterized by a narrow…

(abridged) [...] Methods: In a continued study of the molecular core population of the Pipe Nebula, we present a molecular-line survey of 52 cores. Previous research has shown a variety of different chemical evolutionary stages among the…

Solar and Stellar Astrophysics · Physics 2014-09-05 Jan Forbrich , Karin Öberg , Charles J. Lada , Marco Lombardi , Alvaro Hacar , João Alves , Jill M. Rathborne

We used the new IRAM 30-m FTS backend to perform an unbiased ~15 GHz wide survey at 3 mm toward the Pipe Nebula young diffuse starless cores. We found an unexpectedly rich chemistry. We propose a new observational classification based on…

Astrophysics of Galaxies · Physics 2015-06-03 P. Frau , J. M. Girart , M. T. Beltran

The relationship between submillimeter (submm) dust emission polarization and near-infrared (NIR) $H$-band polarization produced by dust dichroic extinction was studied for the cold starless dense core FeSt 1-457. The distribution of…

Multi-wavelength observations in the sub-mm regime provide information on the distribution of both the dust column density and the effective dust temperature in molecular clouds. In this study, we created high-resolution and…

Astrophysics of Galaxies · Physics 2018-11-28 Birgit Hasenberger , Marco Lombardi , João Alves , Jan Forbrich , Alvaro Hacar , Charles J. Lada

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 extinction and comprise a starless population in a very early stage…

Astrophysics · Physics 2009-11-13 J. M. Rathborne , C. J. Lada , A. A. Muench , J. F. Alves , M. Lombardi

We have considered the thermal equilibrium in pre-protostellar cores in the approximation where the dust temperature is independent of interactions with the gas and where the gas is heated both by collisions with dust grains and ionization…

Astrophysics · Physics 2009-11-07 D. Galli , M. Walmsley , J. Goncalves

The density and temperature structures of dense cores in the L1495 cloud of the Taurus star-forming region are investigated using Herschel SPIRE and PACS images in the 70 $\mu$m, 160 $\mu$m, 250 $\mu$m, 350 $\mu$m and 500 $\mu$m continuum…

(abridged) Methods: We derive maps of submillimeter dust optical depth and effective dust temperature from Herschel data that were calibrated against Planck. After calibration, we then fit a modified blackbody to the long-wavelength…

Solar and Stellar Astrophysics · Physics 2015-08-19 Jan Forbrich , Charles J. Lada , Marco Lombardi , Carlos Roman-Zuñiga , João Alves

Aims. Our goals are to compare the CS, N2H+ and dust distributions in a representative sample of high-mass star forming dense cores and to determine the physical and chemical properties of these cores. Methods. We compare the results of…

Astrophysics · Physics 2009-11-11 L. Pirogov , I. Zinchenko , P. Caselli , L. E. B. Johansson

Dusty starless cores play an important role in regulating the initial phases of the formation of stars and planets. In their interiors, dust grains coagulate and ice mantles form, thereby changing the millimeter emissivities and hence the…

Cold ($\sim$10 K) and dense ($\sim$10$^{5}$ cm$^{-3}$) cores of gas and dust within molecular clouds, known as starless and dynamically evolved prestellar cores, are the birthplaces of low-mass ($M$ $\leq$ few M$_\odot$) stars. As…

Astrophysics of Galaxies · Physics 2024-08-22 Samantha Scibelli , Yancy Shirley , Andrés Megías , Izaskun Jiménez-Serra

Context. The Pipe nebula is a molecular cloud that lacks star formation feedback and has a relatively simple morphology and velocity structure. This makes it an ideal target to test cloud evolution through collisions. Aims. We aim at…

Astrophysics of Galaxies · Physics 2015-01-28 Pau Frau , Josep M. Girart , Felipe Alves , Gabriel A. P. Franco , Toshikazu Onishi , Carlos G. Román-Zúñiga

Radial density profiles for the sample of dense cores associated with high-mass star-forming regions from southern hemisphere have been derived using the data of observations in continuum at 250 GHz. Radial density profiles for the inner…

Astrophysics of Galaxies · Physics 2014-11-20 Lev E. Pirogov

The structure of the dusty circumstellar envelopes (CSEs) of proto-planetary nebulae (PPNs) reveals the mass-loss history of these sources and how such histories may differ for elliptical (SOLE) and bipolar (DUPLEX) PPNs. To study the PPN…

Astrophysics · Physics 2008-11-26 Toshiya Ueta , Koji Murakawa , Margaret Meixner

Identified as extinction features against the bright Galactic mid-infrared background, infrared dark clouds (IRDCs) are thought to harbor the very earliest stages of star and cluster formation. In order to better characterize the properties…

Solar and Stellar Astrophysics · Physics 2015-05-18 J. M. Rathborne , J. M. Jackson , E. T. Chambers , I. Stojimirovic , R. Simon , R. Shipman , W. Frieswijk

Starless cores represent the initial stage of evolution toward (proto)star formation, and a subset of them, known as prestellar cores, with high density (~ 10^6 cm^-3 or higher) and being centrally concentrated are expected to be embryos of…

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