Access to Astronomical Catalogues

← Click to display the menu
J/A+A/606/A100      YSOs in California Molecular Cloud       (Lada+, 2017)

HP2 survey. III. The California Molecular Cloud: A sleeping giant revisited. Lada C.J., Lewis J.A., Lombardi M., Alves J. <Astron. Astrophys. 606, A100 (2017)> =2017A&A...606A.100L (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; YSOs ; Photometry, classification Keywords: stars: formation - dust, extinction - ISM: clouds - ISM: individual: California Molecular Cloud Abstract: We present new high resolution and dynamic range dust column density and temperature maps of the California Molecular Cloud derived from a combination of Planck and Herschel dust-emission maps, and 2MASS NIR dust-extinction maps. We used these data to determine the ratio of the 2.2µm extinction coefficient to the 850µm opacity and found the value to be close to that found in similar studies of the Orion B and Perseus clouds but higher than that characterizing the Orion A cloud, indicating that variations in the fundamental optical properties of dust may exist between local clouds. We show that over a wide range of extinction, the column density probability distribution function (pdf) of the cloud can be well described by a simple power law (i.e., PDFN∝AK-n) with an index (n=4.0±0.1) that represents a steeper decline with AK than found (n~=3) in similar studies of the Orion and Perseus clouds. Using only the protostellar population of the cloud and our extinction maps we investigate the Schmidt relation, that is, the relation between the protostellar surface density, Σ*, and extinction, AK, within the cloud. We show that Σ* is directly proportional to the ratio of the protostellar and cloud pdfs, i.e., PDF*(AK)/PDFN(AK). We use the cumulative distribution of protostars to infer the functional forms for both Σ* and PDF*. We find that Σ* is best described by two power-law functions. At extinctions AK≤2.5mag, Σ*∝AKβ with β=3.3 while at higher extinctions β=2.5, both values steeper than those (~=2) found in other local giant molecular clouds (GMCs). We find that PDF* is a declining function of extinction also best described by two power-laws whose behavior mirrors that of Σ*. Our observations suggest that variations both in the slope of the Schmidt relation and in the sizes of the protostellar populations between GMCs are largely driven by variations in the slope, n, of PDFN(AK). This confirms earlier studies suggesting that cloud structure plays a major role in setting the global star formation rates in GMCs Description: The CMC was observed by the all-sky Planck observatory and by the Herschel Space Observatory as part of the "Auriga-California" program (Harvey et al. 2013, Cat J/ApJ/764/133). The Herschel data we used consisted of observations obtained in parallel mode simultaneously using the PACS and SPIRE instruments. For the purposes of this study we use Herschel observations made in the PACS 160um band, and the SPIRE 250um, 350um and 500um bands. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 58 177 Young stellar objects in the California Molecular Cloud
See also: J/A+A/587/A106 : Perseus dust optical depth & column density maps (Zari+, 2016) Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Sequential number 4 A1 --- n_Seq [*] Note on Seq 6- 7 I2 h RAh Right ascension (J2000) 9- 10 I2 min RAm Right ascension (J2000) 12- 16 F5.2 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign (J2000) 19- 20 I2 deg DEd Declination (J2000) 22- 23 I2 arcmin DEm Declination (J2000) 25- 29 F5.2 arcsec DEs Declination (J2000) 31- 35 F5.3 mag AK Infrared extinction 37- 41 F5.3 mag e_AK rms uncertainty on AK 43- 45 I3 --- IDB ? Broekhoven-Fiene et al. (2014, Cat. J/ApJ/786/37) identification number, ([BMH2014] NNN in Simbad) 47- 49 A3 --- ClassB Broekhoven-Fiene et al. (2014, Cat. J/ApJ/786/37) classification (1) 51- 52 I2 --- IDH ? Harvey et al. (2013, Cat. J/ApJ/764/133) identification number ([HFG2013] NN in Simbad) 54- 56 A3 --- ClassH Harvey et al. (2013, Cat. J/ApJ/764/133) classification (1) 58 A1 --- Class [PDS] Classification (2)
Note (1): Classification as follows: 0 = the most dust-enshrouded objects (not detectable at λ<20um) I = sources with α > 0.3 F = flat spectrum (-0.3 < α < 0.3) II = sources with -1.6 ≤ α < -0.3 III = sources with α < -1.6 Note (2): Classification as follows: P = protostar (Class 0/I), (dM/dt)/M*≥10-6 and Menv/M*≥0.05 D = disk (Class II), (dM/dt)/M*<10-6 and Mdisk/M*≥10-6 S = star (Class III) (dM/dt)/M*<10-6 and Mdisk/M*<10-6
History: From electronic version of the journal References: Lombardi et al., Paper I 2015A&A...576L...1L Zari et al., Paper II 2016A&A...587A.106Z, Cat. J/A+A/587/A106
(End) Patricia Vannier [CDS] 18-Jan-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© Unistra/CNRS