scholarly journals ALMA-IMF. I. Investigating the origin of stellar masses: Introduction to the Large Program and first results

2021 ◽  
Author(s):  
F. Motte ◽  
S. Bontemps ◽  
T. Csengeri ◽  
Y. Pouteau ◽  
F. Louvet ◽  
...  
Keyword(s):  
Large Program ◽  
First Results ◽  
Stellar Masses

scholarly journals GASP: Gas stripping and the outskirts of galaxies as a function of environment

2016 ◽  
Vol 11 (S321) ◽  
pp. 202-204
Author(s):  
Bianca Poggianti ◽  
Keyword(s):  
Gas Stripping ◽  
Large Program ◽  
Gas Removal ◽  
The Galaxy ◽  
First Results ◽  
Galaxy Center ◽  
Removal Processes ◽  
Stellar Masses

AbstractWe present GASP, an ongoing ESO Large Program with MUSE aiming to study gas removal processes from galaxies at low redshift. GASP targets 100 galaxies with tails, tentacles and one-sided debris. MUSE data allows a detailed investigation of the ionized stripped gas, as well as of the gas and stars within the galaxy out to large distances from the galaxy center. We show the first results for two of the GASP galaxies that are striking cluster jellyfish galaxies of stellar masses ~ 1011M⊙.

scholarly journals The spectral energy distributions of the entire Herschel Reference Survey

2011 ◽  
Vol 7 (S284) ◽  
pp. 283-285
Author(s):  
Laure Ciesla ◽  
Keyword(s):  
Far Infrared ◽  
Infrared Emission ◽  
Spectral Energy ◽  
Physical Parameters ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Distant Galaxies ◽  
First Results ◽  
Nearby Galaxies ◽  
Stellar Masses

AbstractWe present the spectral energy distributions (SED) of the 323 galaxies of the Herschel Reference Survey. In order to provide templates for nearby galaxies calibrated on physical parameters, we computed mean SEDs per bin of morphological types and stellar masses. They will be very useful to study more distant galaxies and their evolution with redshift. This preliminary work aims to study how the most commonly used libraries (Chary & Elbaz 2001, Dale & Helou 2002 and Draine & Li 2007) reproduce the far-infrared emission of galaxies. First results show that they reproduce well the far-infrared part of mean SEDs. For single galaxies the Draine & Li (2007) models seem to reproduce very well the far-infrared emission, as does the Dale & Helou (2002).

Fifty AU Study of the chemistry in the disk/envelope system of Solar-like protostars (FAUST) Large program first results: the hot corino in L1551 IRS5

2020 ◽  
Author(s):  
Eleonora Bianchi ◽  
Satoshi Yamamoto ◽  
Cecilia Ceccarelli ◽  
Claire Chandler ◽  
Claudio Codella ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Planet Formation ◽  
Methyl Formate ◽  
Line Emission ◽  
Class I ◽  
Gas Temperature ◽  
Origin And Evolution ◽  
The North ◽  
Large Program ◽  
First Results

<p>Detection of hot corinos in Solar-like protostars has been so far mostly limited to Class 0 objects, hampering our understanding of their origin and evolution. Recent evidence suggests that planet formation probably starts already in Class I protostars, representing a key step in our understanding of their chemical composition at the planet formation scale. Therefore, understanding the fate of hot corinos in Class I protostars has become of paramount importance. In this context, we report the discovery of a hot corino at the heart of the prototypical Class I source L1551 IRS5, obtained via ALMA observations as part of the Large Program FAUST (Fifty AU Study of the chemistry in the disk/envelope system of Solar-like protostars). More specifically, FAUST is the first ALMA Large Program based on astrochemistry and is designed to survey the chemical composition of a sample of 13 Class 0 and I protostars at the planet-formation scale.</p> <p>We detected in L1551 IRS 5 several emission lines from interstellar complex organic molecules (iCOMs) such as methanol and its most abundant isotopologues, as well as methyl formate and ethanol.  The line emission is bright toward the north component (N), although a hot corino in the south component, cannot be excluded. The non-LTE analysis of the methanol lines towards N provides constraints on the gas temperature (~ 100 K), density (≥ 1.5 x 10<sup>8</sup> cm<sup>-3</sup>) and emitting size (~0.15”, i.e. ~ 10 au in radius). The lines are predicted to be optically thick, the <sup>13</sup>CH<sub>3</sub>OH line having an opacity ≥ 2. The methyl formate and ethanol column densities relative to methanol are ≤ 0.03 and ≤ 0.015, respectively, compatible with those measured in Class 0 sources. Thus, the present observations towards L1551 IRS5 agree with little chemical evolution in hot corinos from Class 0 to I.</p> <p> </p>

scholarly journals The intriguing life of star-forming galaxies in the redshift range 1 ≤ z ≤ 2 using MASSIV

2012 ◽  
Vol 8 (S295) ◽  
pp. 86-90
Author(s):  
P. Amram ◽  
C. López-Sanjuan ◽  
B. Epinat ◽  
T. Contini ◽  
D. Vergani ◽  
...  
Keyword(s):  
Redshift Range ◽  
Star Forming ◽  
Large Program ◽  
Wide Range ◽  
Major Merger ◽  
High Fraction ◽  
Mass Assembly ◽  
Merger Rate ◽  
Galaxy Population ◽  
Stellar Masses

AbstractMASSIV (Mass Assembly Survey with SINFONI in VVDS) is an ESO large program which consists of 84 star-forming galaxies, spanning a wide range of stellar masses, observed with the IFU SINFONI on the VLT, in the redshift range 1 ≤ z ≤ 2. To be representative of the normal galaxy population, the sample has been selected from a well-defined, complete and representative parent sample. The kinematics of individual galaxies reveals that 58% of the galaxies are slow rotators, which means that a high fraction of these galaxies should probably be formed through major merger processes which might have produced gaseous thick or spheroidal structures supported by velocity dispersion rather than by rotation. Computations on the major merger rate from close pairs indicate that a typical star-forming galaxy underwent ~0.4 major mergers in the last ~9.5 Gyr, showing that merging is a major process driving mass assembly into the red sequence galaxies. These objects are also intriguing due to the fact that more than one galaxy over four is more metal-rich in its outskirts than in its center.

scholarly journals The MiMeS project: first results

2008 ◽  
Vol 4 (S259) ◽  
pp. 387-388
Author(s):  
Jason H. Grunhut ◽  
E. Alecian ◽  
D. A. Bohlender ◽  
J.-C. Bouret ◽  
H. Henrichs ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Massive Star ◽  
Massive Stars ◽  
Chemical Elements ◽  
Statistical Properties ◽  
The Sun ◽  
Large Program ◽  
Stellar Component ◽  
First Results ◽  
The Universe

AbstractMassive stars are those stars with initial masses above about 8 times that of the sun, eventually leading to catastrophic explosions in the form of supernovae. These represent the most massive and luminous stellar component of the Universe, and are the crucibles in which the lion's share of the chemical elements are forged. These rapidly-evolving stars drive the chemistry, structure and evolution of galaxies, dominating the ecology of the Universe - not only as supernovae, but also during their entire lifetimes - with far-reaching consequences. Although the existence of magnetic fields in massive stars is no longer in question, our knowledge of the basic statistical properties of massive star magnetic fields is seriously incomplete. The Magnetism in Massive Stars (MiMeS) Project represents a comprehensive, multidisciplinary strategy by an international team of recognized researchers to address the “big questions” related to the complex and puzzling magnetism of massive stars. This paper present the first results of the MiMeS Large Program at the Canada-France-Hawaii Telescope.

scholarly journals VIS3COS

2018 ◽  
Vol 620 ◽  
pp. A186 ◽  
Author(s):  
Ana Paulino-Afonso ◽  
David Sobral ◽  
Behnam Darvish ◽  
Bruno Ribeiro ◽  
Andra Stroe ◽  
...  
Keyword(s):  
Formation Rate ◽  
Line Strength ◽  
Stellar Mass ◽  
High Density ◽  
Redshift Distribution ◽  
Massive Galaxies ◽  
Wide Range ◽  
First Results ◽  
Single Dataset ◽  
Stellar Masses

We present the VIMOS Spectroscopic Survey of a Supercluster in the COSMOS field (VIS3COS) at z ∼ 0.84. We use VIMOS high-resolution spectra (GG475 filter) to spectroscopically select 490 galaxies in and around the superstructure and an additional 481 galaxies in the line of sight. We present the redshift distribution, the catalogue to be made public, and the first results on the properties of individual galaxies and stacked spectra (3500 Å < λ <  4200 Å rest-frame). We probe a wide range of densities and environments (from low-density field to clusters and rich groups). We find a decrease in the median star formation rate from low- to high-density environments in all bins of stellar mass and a sharp rise of the quenched fraction (from ∼10% to ∼40 − 60%) of intermediate-stellar-mass galaxies (10 <  log10 (M⋆/M⊙) <  10.75) from filaments to clusters. The quenched fraction for massive galaxies shows little dependence on environment, being constant at ∼30 − 40%. We find a break in the strength of the [O II] emission, with nearly constant line equivalent widths at lower densities (∼ − 11 Å) and then a drop to ∼ − 2.5 Å towards higher densities. The break in the [OII] line strength happens at similar densities (log10(1 + δ) ∼ 0.0 − 0.5) as the observed rise in the quenched fraction. Our results may provide further clues regarding the different environmental processes affecting galaxies with different stellar masses and highlight the advantages of a single dataset in the COSMOS field probing a wide range of stellar masses and environments. We hypothesise that quenching mechanisms are enhanced in high-density regions.

scholarly journals Dwarf Elliptical Galaxies in the Cena and Sculptor Groups

1998 ◽  
Vol 11 (1) ◽  
pp. 107-108
Author(s):  
H. Jerjen ◽  
K.C. Freeman ◽  
B. Binggeli
Keyword(s):  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Elliptical Galaxies ◽  
Large Program ◽  
Irregular Galaxies ◽  
First Results ◽  
Complete Survey ◽  
Group Members ◽  
Dwarf Elliptical Galaxies ◽  
Dwarf Irregular Galaxies

Côté (1995) surveyed the nearby Centaurus A (Cen A) and Sculptor (Sci) group regions in the search for gas-rich, dwarf irregular galaxies (Irr) which are associated with these galaxy aggregates. 36 Irrs have been found and confirmed as new group members via 21cm/Hα redshifts. In finding this large number of Irrs, the question rises whether systems from the other dwarf galaxy family, the gas-poor dwarf ellipticals (dE), also exist in the two groups. So far nothing is known about dE membership but taking into account the morphology-density relation for dwarfs (Binggeli et al. 1990) a number ratio Irr/dE≈ 1 - 2 would be expected. Prompted by these “missing” dEs we started a large program to identify and study dEs in Cen A and Sci. The main scientific goals are (1) to find dE candidates and to establish group membership via velocity or distance and (2) to estimate the luminosity function (LF) of dwarf galaxies to the faintest possible luminosities. For the two groups, being respectively at a mean distance of 4.0 Mpc and 2.5 Mpc, we will be able to reach dwarf galaxies 4-5 magnitudes fainter than in the previous studies in the Virgo and Fornax clusters and the five groups Leo I, Dorado, NGC1400, NGC5044, and Antlia (Sandage et al. 1985, Ferguson &: Sandage 1990). We briefly outline here first results from the CenA group. All details about the complete survey including Scl will be presented in Jerjen et al. (1997)

scholarly journals ESO large program on physical studies of Transneptunian Objects and Centaurs: Visible photometry – First results

2002 ◽  
Vol 395 (1) ◽  
pp. 297-303 ◽  
Author(s):  
H. Boehnhardt ◽  
A. Delsanti ◽  
A. Barucci ◽  
O. Hainaut ◽  
A. Doressoundiram ◽  
...  
Keyword(s):  
Large Program ◽  
First Results ◽  
Transneptunian Objects

scholarly journals Probing episodic accretion with chemistry: CALYPSO observations of the very-low-luminosity Class 0 protostar IRAM 04191+1522

2020 ◽  
Vol 643 ◽  
pp. A123
Author(s):  
S. Anderl ◽  
S. Maret ◽  
S. Cabrit ◽  
A. J. Maury ◽  
A. Belloche ◽  
...  
Keyword(s):  
Line Emission ◽  
Physical Structure ◽  
Time Dependent ◽  
High Angular Resolution ◽  
Mass Star ◽  
Object A ◽  
Large Program ◽  
Accretion Rates ◽  
Low Mass ◽  
Stellar Masses

Context. The process of mass accretion in the earliest phases of star formation is still not fully understood: does the accretion rate smoothly decline with the age of the protostar or are there short, intermittent accretion bursts? The latter option would also yield the possibility for very low-luminosity objects (VeLLOs) to be precursors of solar-type stars, even though they do not seem to have sufficiently high accretion rates to reach stellar masses during their protostellar lifetime. Nevertheless, probing such intermittent events in the deeply embedded phase is not easy. Chemical signatures in the protostellar envelope can trace a past accretion burst. Aims. We aim to explore whether or not the observed C18O and N2H+ emission pattern towards the VeLLO IRAM 04191+1522 can be understood in the framework of a scenario where the emission is chemically tracing a past accretion burst. Methods. We used high-angular-resolution Plateau de Bure Interferometer (PdBI) observations of C18O and N2H+ towards IRAM 04191+1522 that were obtained as part of the CALYPSO IRAM Large Program (Continuum And Lines in Young ProtoStellar Objects). We model these observations using a chemical code with a time-dependent physical structure coupled with a radiative transfer module, where we allow for variations in the source luminosity. Results. We find that the N2H+ line emission shows a central hole, with the N2H+ emission peaking at a radius of about 10′′ (1400 au) from the source, while the C18O emission is compact (1.3′′ FWHM, corresponding to 182 au). The morphology of these two lines cannot be reproduced with a constant luminosity model based on the present-day internal luminosity (0.08 L⊙). However, the N2H+ peaks are consistent with a constant-luminosity model of 12 L⊙. Using a model with time-dependent temperature and density profiles, we show that the observed N2H+ peak emission could indeed be caused by a past accretion burst with a luminosity 150 times higher than the present-day luminosity. Such a burst should have occurred a couple of hundred years ago. Conclusions. We suggest that an accretion burst occurred in IRAM 04191+1522 in the recent past. If such bursts are common and sufficiently long in VeLLOs, they could lead to higher accretion onto the central object than their luminosity suggests. For IRAM 04191 in particular, our results yield an estimated final mass of 0.2–0.25 M⊙ by the end of the Class 0 phase, which would make this object a low-mass star rather than a brown dwarf. More generally, our analysis demonstrates that the combination of observations of N2H+ and C18O is a more reliable diagnostic of past outburst activity than C18O or N2H+ emission alone.

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