- ID:
- ivo://CDS.VizieR/J/A+A/619/A52
- Title:
- Dense cores and YSOs in Lupus complex
- Short Name:
- J/A+A/619/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of the dense cores and YSOs/protostars of the Lupus I, Lupus III, and Lupus IV molecular clouds. Sources were extracted from the far-infrared photometric maps at 70, 160, 250, 350 and 500um acquired with the Spectral and Photometric Imaging Receiver (SPIRE) and the Photodetector Array Camera and Spectrometer (PACS) instruments onboard the Herschel Space Observatory, within the Herschel Gould Belt Survey project. A total of 532 dense cores, out of which 103 are presumably prestellar in nature, and 38 YSOs/protostars have been detected in the three clouds. The physical properties of the objects were derived by fitting their spectral energy distributions. Almost all the prestellar cores are associated with filaments against only about one third of the unbound cores and YSOs/ protostars. Prestellar core candidates are found even in filaments that are on average thermally sub-critical and over a background column density lower than that measured in other star forming regions so far. The core mass function of the prestellar cores peaks between 0.2 and 0.3 solar masses and it is compatible with the log-normal shape found in other regions. Herschel data reveal several, previously undetected, protostars and new candidates of Class 0 and Class II with transitional disks. We estimate the evolutionary status of the YSOs/protostars using two independent indicators: the {alpha} index and the fitting of the spectral energy distribution from near- to far-infrared wavelengths. For 70% of the objects, the evolutionary stages derived with the two methods are in agreement.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/710/1247
- Title:
- Dense cores in Gould Belt clouds
- Short Name:
- J/ApJ/710/1247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the SCUBA Legacy Catalogue (850um) and Spitzer Space Telescope (3.6-70um), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by Submillimeter Common-User Bolometer Array (SCUBA) as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) for the five clouds. We find best-fit slopes to the high-mass end of the CMFs of -1.26+/-0.20, -1.22+/-0.06, -0.95+/-0.20, and -1.67+/-0.72 for Ophiuchus, Taurus, Perseus, and Orion, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/462/L17
- Title:
- Dense cores in interstellar molecular clouds
- Short Name:
- J/A+A/462/L17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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 understanding of the origin of the IMF. To date, observations have presented somewhat contradictory evidence relating to this issue. In this paper we propose to derive the mass function of a complete sample of dense molecular cores in a single cloud employing a robust method that uses uses extinction of background starlight to measure core masses and enables the reliable extension of such measurements to lower masses than previously possible. We use a map of near-infrared extinction in the nearby Pipe dark cloud to identify the population of dense cores in the cloud and measure their masses.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A104
- Title:
- Dense cores in L1495/B213 complex
- Short Name:
- J/A+A/574/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cloud fragmentation into dense cores is a critical step in the process of star formation. A number of recent observations show that it is connected to the filamentary structure of the gas, but the processes responsible for core formation remain mysterious. We studied the kinematics and spatial distribution of the dense gas in the L1495/B213 filamentary region of the Taurus molecular cloud with the goal of understanding the mechanism of core formation. We mapped the densest regions of L1495/B213 in N_2_H^+^(1-0) and C_18_O(2-1) with the IRAM 30m telescope, and complemented these data with archival dust-continuum observations from the Herschel Space Observatory.
4335. Dense cores in Perseus
- ID:
- ivo://CDS.VizieR/J/ApJ/696/298
- Title:
- Dense cores in Perseus
- Short Name:
- J/ApJ/696/298
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the chemistry, temperature, and dynamical state of a sample of 193 dense cores or core candidates in the Perseus Molecular cloud and compare the properties of cores associated with young stars and clusters with those which are not. The combination of our NH3 and CCS observations with previous millimeter, submillimeter, and Spitzer data available for this cloud enables us both to determine core properties precisely and to accurately classify cores as starless or protostellar.
- ID:
- ivo://CDS.VizieR/J/ApJ/668/1042
- Title:
- Dense cores in Perseus molecular cloud
- Short Name:
- J/ApJ/668/1042
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We survey the kinematics of over 150 candidate (and potentially star-forming) dense cores in the Perseus molecular cloud with pointed N_2_H^+^(1-0) and simultaneous C^18^O(2-1) observations. Our detection rate of N_2_H^+^ is 62%, rising to 84% for SCUBA-selected targets. In agreement with previous observations, we find that the dense N_2_H^+^ targets tend to display nearly thermal line widths, particularly those that appear to be starless (using Spitzer data), indicating that turbulent support on the small scales of molecular clouds is minimal. For those N_2_H^+^ targets that have an associated SCUBA dense core, we find that their internal motions are more than sufficient to provide support against the gravitational force on the cores.
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/342
- Title:
- Dense cores in Taurus L1495 cloud
- Short Name:
- J/MNRAS/459/342
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of dense cores in a ~4{deg}x2{deg} field of the Taurus star-forming region, inclusive of the L1495 cloud, derived from Herschel SPIRE and PACS observations in the 70{mu}m, 160{mu}m, 250{mu}m, 350{mu}m, and 500{mu}m continuum bands. Estimates of mean dust temperature and total mass are derived using modified blackbody fits to the spectral energy distributions. We detect 525 starless cores of which ~10-20 per cent are gravitationally bound and therefore presumably prestellar. Our census of unbound objects is ~85 per cent complete for M>0.015M_{sun}_ in low-density regions (A_V_<~5mag), while the bound (prestellar) subset is ~85 per cent complete for M>0.1M_{sun}_ overall. The prestellar core mass function (CMF) is consistent with lognormal form, resembling the stellar system initial mass function, as has been reported previously. All of the inferred prestellar cores lie on filamentary structures whose column densities exceed the expected threshold for filamentary collapse, in agreement with previous reports. Unlike the prestellar CMF, the unbound starless CMF is not lognormal, but instead is consistent with a power-law form below 0.3M_{sun}_ and shows no evidence for a low-mass turnover. It resembles previously reported mass distributions for CO clumps at low masses (M<~0.3M_{sun}_). The volume density PDF, however, is accurately lognormal except at high densities. It is consistent with the effects of self-gravity on magnetized supersonic turbulence. The only significant deviation from lognormality is a high-density tail which can be attributed unambiguously to prestellar cores.
- ID:
- ivo://CDS.VizieR/J/ApJ/665/1194
- Title:
- Dense cores in the Orion A cloud survey
- Short Name:
- J/ApJ/665/1194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an H^13^CO^+^ (J=1-0) core survey in a large area of 1.5degx0.5deg, covering the whole region of the Orion A molecular cloud, using the Nobeyama 45m radio telescope with the 25 Beam Array Receiver System (BEARS). This survey is unique in that a large area (~48pc^2^) of the cloud was covered with a high spatial resolution of 21" (0.05pc) and with a deep integration (1sigma~0.1K in T*_A_), resulting in a core mass detection of 1.6M_{sun}_. The morphology of the H^13^CO^+^ (J=1-0) emission is very similar to that of the 850um continuum emission. We identified 236 dense cores from our data with the clumpfind algorithm. The cores are close to virial equilibrium, independent of whether they are thermal or turbulent.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/1560
- Title:
- Dense core survey in the Orion B cloud
- Short Name:
- J/ApJ/691/1560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an H^13^CO^+^(J=1-0 at 86.75433GHz) core survey in a large area of 1deg^2^, covering most of the dense region in the Orion B molecular cloud, using the Nobeyama 45m radio telescope with the 25-BEam Array Receiver System. We cataloged 151 dense cores using the clumpfind method. The cores have mean radius, velocity width, and mass of 0.10+/-0.02pc, 0.53+/-0.15km/s, and 8.1+/-6.4M_{sun}_, respectively, which are very similar to those in the Orion A cloud. We examined the spatial relation between our H^13^CO^+^ cores and the 850um cores observed by Johnstone and colleagues in 2001 (Cat. J/ApJ/559/307) and 2006 (Cat. J/ApJ/639/259), and found that there are two types of spatial relationships: H^13^CO^+^ cores with and without the 850um cores. Since the mean density of the 850um cores is higher than that of the H^13^CO^+^ cores, we can interpret the H^13^CO^+^ cores with 850um cores as being more centrally concentrated and hence more evolved, compared with those without.
4340. Dense molecular cores
- ID:
- ivo://CDS.VizieR/J/A+A/288/601
- Title:
- Dense molecular cores
- Short Name:
- J/A+A/288/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)