Perseus Molecular Cloud Complex Research Articles

The JCMT BISTRO Survey: Magnetic Fields Associated with a Network of Filaments in NGC 1333

Abstract We present new observations of the active star formation region NGC 1333 in the Perseus molecular cloud complex from the James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with the POL-2 instrument. The BISTRO data cover the entire NGC 1333 complex (∼1.5 pc × 2 pc) at 0.02 pc resolution and spatially resolve the polarized emission from individual filamentary structures for the first time. The inferred magnetic field structure is complex as a whole, with each individual filament aligned at different position angles relative to the local field orientation. We combine the BISTRO data with low- and high- resolution data derived from Planck and interferometers to study the multiscale magnetic field structure in this region. The magnetic field morphology drastically changes below a scale of ∼1 pc and remains continuous from the scales of filaments (∼0.1 pc) to that of protostellar envelopes (∼0.005 pc or ∼1000 au). Finally, we construct simple models in which we assume that the magnetic field is always perpendicular to the long axis of the filaments. We demonstrate that the observed variation of the relative orientation between the filament axes and the magnetic field angles are well reproduced by this model, taking into account the projection effects of the magnetic field and filaments relative to the plane of the sky. These projection effects may explain the apparent complexity of the magnetic field structure observed at the resolution of BISTRO data toward the filament network.

The JCMT BISTRO Survey: The Magnetic Field of the Barnard 1 Star-forming Region

Abstract We present the POL-2 850 μm linear polarization map of the Barnard 1 clump in the Perseus molecular cloud complex from the B-fields In STar-forming Region Observations survey at the James Clerk Maxwell Telescope. We find a trend of decreasing polarization fraction as a function of total intensity, which we link to depolarization effects toward higher-density regions of the cloud. We then use the polarization data at 850 μm to infer the plane-of-sky orientation of the large-scale magnetic field in Barnard 1. This magnetic field runs north–south across most of the cloud, with the exception of B1-c, where it turns more east–west. From the dispersion of polarization angles, we calculate a turbulence correlation length of 5.0 ± 2.″5 (1500 au) and a turbulent-to-total magnetic energy ratio of 0.5 ± 0.3 inside the cloud. We combine this turbulent-to-total magnetic energy ratio with observations of NH3 molecular lines from the Green Bank Ammonia Survey to estimate the strength of the plane-of-sky component of the magnetic field through the Davis–Chandrasekhar–Fermi method. With a plane-of-sky amplitude of 120 ± 60 μG and a criticality criterion λ c = 3.0 ± 1.5, we find that Barnard 1 is a supercritical molecular cloud with a magnetic field nearly dominated by its turbulent component.

Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex

Chemical diversity of the gas in low-mass protostellar cores is widely recognized. In order to explore its origin, a survey of chemical composition toward 36 Class 0/I protostars in the Perseus molecular cloud complex, which are selected in an unbiased way under certain physical conditions, has been conducted with IRAM 30 m and NRO 45 m telescope. Multiple lines of C2H, c-C3H2 and CH3OH have been observed to characterize the chemical composition averaged over a 1000 au scale around the protostar. The derived beam-averaged column densities show significant chemical diversity among the sources, where the column density ratios of C2H/CH3OH are spread out by 2 orders of magnitude. From previous studies, the hot corino sources have abundant CH3OH but deficient C2H, their C2H/CH3OH column density ratios being relatively low. In contrast, the warm-carbon-chain chemistry (WCCC) sources are found to reveal the high C2H/CH3OH column density ratios. We find that the majority of the sources have intermediate characters between these two distinct chemistry types. A possible trend is seen between the C2H/CH3OH ratio and the distance of the source from the edge of a molecular cloud. The sources located near cloud edges or in isolated clouds tend to have a high C2H/CH3OH ratio. On the other hand, the sources having a low C2H/CH3OH ratio tend to be located in inner regions of the molecular cloud complex. This result gives an important clue to an understanding of the origin of the chemical diversity of protostellar cores in terms of environmental effects.

THESPITZERc2d SURVEY OF LARGE, NEARBY, INTERSTELLAR CLOUDS. XII. THE PERSEUS YSO POPULATION AS OBSERVED WITH IRAC AND MIPS

The Spitzer Space Telescope mapped the Perseus molecular cloud complex with IRAC and MIPS as part of the c2d Spitzer Legacy project. This paper combines the observations from both instruments giving an overview of low-mass star formation across Perseus from 3.6 to 70 micron. We provide an updated list of young stellar objects with new classifications and source fluxes from previous works, identifying 369 YSOs in Perseus with the Spitzer dataset. By synthesizing the IRAC and MIPS maps of Perseus and building on the work of previous papers in this series (Jorgensen et al. 2006, Rebull et al. 2007), we present a current census of star formation across the cloud and within smaller regions. 67% of the YSOs are associated with the young clusters NGC 1333 and IC 348. The majority of the star formation activity in Perseus occurs in the regions around the clusters, to the eastern and western ends of the cloud complex. The middle of the cloud is nearly empty of YSOs despite containing regions of high visual extinction. The western half of Perseus contains three-quarters of the total number of embedded YSOs (Class 0+I and Flat SED sources) in the cloud and nearly as many embedded YSOs as Class II and III sources. Class II and III greatly outnumber Class 0+I objects in eastern Perseus and IC 348. These results are consistent with previous age estimates for the clusters. Across the cloud, 56% of YSOs and 91% of the Class 0+I and Flat sources are in areas where Av > 5 mag, indicating a possible extinction threshold for star formation.

Evidence for grain growth in molecular clouds: A Bayesian examination of the extinction law in Perseus

We investigate the shape of the extinction law in two 1-degree square fields of the Perseus Molecular Cloud complex. We combine deep red-optical (r, i, and z-band) observations obtained using Megacam on the MMT with UKIDSS near-infrared (J, H, and K-band) data to measure the colours of background stars. We develop a new hierarchical Bayesian statistical model, including measurement error, intrinsic colour variation, spectral type, and dust reddening, to simultaneously infer parameters for individual stars and characteristics of the population. We implement an efficient MCMC algorithm utilising generalised Gibbs sampling to compute coherent probabilistic inferences. We find a strong correlation between the extinction (Av) and the slope of the extinction law (parameterized by Rv). Because the majority of the extinction toward our stars comes from the Perseus molecular cloud, we interpret this correlation as evidence of grain growth at moderate optical depths. The extinction law changes from the diffuse value of Rv = 3 to the dense cloud value of Rv = 5 as the column density rises from Av = 2 mags to Av = 10 mags. This relationship is similar for the two regions in our study, despite their different physical conditions, suggesting that dust grain growth is a fairly universal process.

Astrometry of H$_{2}$ O Masers in Nearby Star-Forming Regions with VERA. IV. L 1448 C

Abstract We have carried out multi-epoch VLBI observations with VERA (VLBI Exploration of Radio Astrometry) of 22 GHz H$_{2}$ O masers associated with a Class 0 protostar, L 1448 C, in the Perseus molecular cloud. The maser features trace the base of a collimated bipolar jet driven by one of the infrared counter parts of L 1448 C, named as L 1448 C(N) or L 1448-mm A. We detected possible evidence for apparent acceleration and precession of the jet according to the three-dimensional velocity structure. Based on phase-referencing VLBI astrometry, we successfully detected an annual parallax of the H$_{2}$ O maser in L 1448 C to be 4.31$\ \pm\ $ 0.33 milliarcseconds (mas), which corresponds to a distance of 232$\ \pm\ $ 18 pc from the Sun. The present result is in good agreement with that of another H$_{2}$ O maser source, NGC 1333 SVS 13, in the Perseus molecular cloud, 235 pc. It is also consistent with the photometric distance, 220 pc. Thus, the distance to the western part of the Perseus molecular cloud complex would be constrained to be about 235 pc, rather than a larger value, 300 pc, previously reported.

THE COMPLETE SURVEY OF OUTFLOWS IN PERSEUS

We present a study on the impact of molecular outflows in the Perseus molecular cloud complex using the COMPLETE survey large-scale 12CO(1-0) and 13CO(1-0) maps. We used three-dimensional isosurface models generated in RA-DEC-Velocity space to visualize the maps. This rendering of the molecular line data allowed for a rapid and efficient way to search for molecular outflows over a large (~ 16 sq. deg.) area. Our outflow-searching technique detected previously known molecular outflows as well as new candidate outflows. Most of these new outflow-related high-velocity features lie in regions that have been poorly studied before. These new outflow candidates more than double the amount of outflow mass, momentum, and kinetic energy in the Perseus cloud complex. Our results indicate that outflows have significant impact on the environment immediately surrounding localized regions of active star formation, but lack the energy needed to feed the observed turbulence in the entire Perseus complex. This implies that other energy sources, in addition to protostellar outflows, are responsible for turbulence on a global cloud scale in Perseus. We studied the impact of outflows in six regions with active star formation within Perseus of sizes in the range of 1 to 4 pc. We find that outflows have enough power to maintain the turbulence in these regions and enough momentum to disperse and unbind some mass from them. We found no correlation between outflow strength and star formation efficiency for the six different regions we studied, contrary to results of recent numerical simulations. The low fraction of gas that potentially could be ejected due to outflows suggests that additional mechanisms other than cloud dispersal by outflows are needed to explain low star formation efficiencies in clusters.

Outflows and Turbulence in Young Stellar Clusters — An Observer's View

AbstractRecent numerical studies have focused their interest on the impact outflows have on the cloud's turbulence. The contradictory results obtained by these studies indicate that it is essential for observers to provide the required data to constrain the models. Here we discuss the impact of outflows on the environment surrounding clusters of young stellar objects, from an observer's point of view. We have conducted several studies of outflows in different active star-forming regions. In all cases it is clear that outflows have the power to sustain the observed turbulence in the gas surrounding protostellar clusters. We investigate whether there is a correlation between outflow strength and star formation efficiency, as predicted by numerical simulations, for six different regions in the Perseus molecular cloud complex. We argue that results of other recent studies that use CO line maps to study the turbulence driving length should not be used to discard outflows as major drivers of turbulence in clusters.

THE PERILS OF CLUMPFIND: THE MASS SPECTRUM OF SUBSTRUCTURES IN MOLECULAR CLOUDS

We study the mass spectrum of sub-structures in the Perseus Molecular Cloud Complex traced by 13 CO (1‐ 0), finding that dN/dM / M -2.4 for the standard Clumpfind parameters. This result does not a gree with the classical dN/dM/ M -1.6 . To understand this discrepancy we study the robustness of the mass spectrum derived using the Clumpfind algorithm. Both 2D and 3D Clumpfind versio ns are tested, using 850 µm dust emission and 13 CO spectral-line observations of Perseus, respectively. T he effect of varying threshold is not important, but varying stepsize produces a different effect for 2D and 3D cases. In the 2D case, where emission is relatively isolated (associated with only the densest peaks in t he cloud), the mass spectrum variability is negligible compared to the mass function fit uncertainties. In the 3D cas e, however, where the 13 CO emission traces the bulk of the molecular cloud, the number of clumps and the derived mass spectrum are highly correlated with the stepsize used. The distinction between “2D and “3D here is more importantly also a distinction between “sparse and “crowded emission. In any “crowded case, Clumpfind should not be used blindly to derive mass functions. Clumpfind’s output in the “crowded case can still offer a statistical description of emission useful in inter-comparisons, but the clump-list should not be treated as a robust region decomposition suitable to generate a physically-meaningful mass function. We conclude that the 13 CO mass spectrum depends on the observations resolution, due to the hierarchical structur e of MC. Subject headings:ISM: clouds — stars: formation — ISM: molecules — ISM: individual (Perseus molecular complex)

Evidence for the Naphthalene Cation in a Region of the Interstellar Medium with Anomalous Microwave Emission

We report high resolution spectroscopy of the moderately reddened (A$_V$=3) early type star Cernis 52 located in a region of the Perseus molecular cloud complex with anomalous microwave emission. In addition to the presence of the most common diffuse interstellar bands (DIBs) we detect two new interstellar or circumstellar bands coincident to within 0.01% in wavelength with the two strongest bands of the naphthalene cation (C$_{10}$H$_{8}^+$) as measured in gas-phase laboratory spectroscopy at low temperatures and find marginal evidence for the third strongest band. Assuming these features are caused by the naphthalene cation, from the measured intensity and available oscillator strengths we find that 0.008 % of the carbon in the cloud could be in the form of this molecule. We expect hydrogen additions to cause hydronaphthalene cations to be abundant in the cloud and to contribute via electric dipole radiation to the anomalous microwave emission. The identification of new interstellar features consistent with transitions of the simplest polycyclic aromatic hydrocarbon adds support to the hypothesis that this type of molecules are the carriers of both diffuse interstellar bands and anomalous microwave emission.

Current Star Formation in the Perseus Molecular Cloud: Constraints from Unbiased Submillimeter and Mid‐Infrared Surveys

We present a census of the population of deeply embedded young stellar objects (YSOs) in the Perseus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the Cores to Disks (c2d) legacy team and JCMT SCUBA submillimeter maps from the COMPLETE team. The mid-infrared sources detected at 24 μm and having [3.6] - [4.5] > 1 are located close to the center of the SCUBA cores, typically within 15'' of their peaks. The narrowness of the spatial distribution of mid-infrared sources around the peaks of the SCUBA cores suggests that no significant dispersal of the newly formed YSOs has occurred. This argues against the suggestion that motions of protostars regulate the timescales over which significant (Bondi-Hoyle) accretion can occur. The YSOs are found to have red [3.6] - [4.5] and [8.0] - [24] colors, but not comparable red [5.8] - [8.0] colors. The most deeply embedded YSOs are found in regions with high extinction, AV ≥ 5, similar to the extinction threshold observed for the SCUBA cores. All the SCUBA cores with high concentrations have embedded YSOs, but not all cores with low concentrations are starless. From the above considerations, a relatively unbiased sample of 49 deeply embedded YSOs is constructed. Embedded YSOs are found in 40 of the 72 SCUBA cores, with only three cores harboring multiple embedded YSOs within 15''. The equal number of SCUBA cores with and without embedded YSOs suggests that the timescale for the evolution through the dense prestellar stages, where the cores are recognized in the submillimeter maps and have central densities of 5 × 104-1 × 105 cm-3, is similar to the timescale for the embedded protostellar stages. The current star formation efficiency of cores is estimated to be approximately 10%-15%. In contrast, the star formation efficiency averaged over the cloud lifetime and compared to the total cloud mass is only a few percent, reflecting also the efficiency in assembling cloud material into the dense cores actually forming stars.

TheSpitzerc2d Survey of Large, Nearby, Interstellar Clouds. III. Perseus Observed with IRAC

We present observations of 3.86 sq. deg. of the Perseus molecular cloud complex with the Spitzer Space Telescope Infrared Array Camera (IRAC). The maps show strong extended emission arising from shocked H2 in outflows in the region and from polycyclic aromatic hydrocarbon features. More than 120,000 sources are extracted toward the cloud. Based on their IRAC colors and comparison to off-cloud and extragalactic fields, we identify 400 candidate young stellar objects. About two thirds of these are associated with the young clusters IC348 and NGC1333, while the last third is distributed over the remaining cloud. We classify the young stellar objects according to the traditional scheme based on the slope of their spectral energy distributions. Significant differences are found for the numbers of embedded Class I objects relative to more evolved Class II objects in IC348, NGC1333 and the remaining cloud with the embedded Class I and "flat spectrum" YSOs constituting 14%, 36% and 47% of the total number of YSOs identified in each of these regions. The high number of Class I objects in the extended cloud (61% of the Class I objects in the entire cloud) suggests that a significant fraction of the current star formation is occuring outside the two main clusters. Finally we discuss a number of outflows and identify their driving sources, including the known deeply embedded Class 0 sources outside the two major clusters. The Class 0 objects are found to be detected by Spitzer and have very red [3.6]-[4.5] colors but do not show similarly red [5.8]-[8.0] colors. The Class 0 objects are easily identifiable in color-color diagrams plotting these two colors but are problematic to extract automatically due to the extended emission from shocked gas or scattered light in cavities related to the associated outflows.

The COMPLETE Nature of the Warm Dust Shell in Perseus

The Perseus molecular cloud complex is a &30pc long chain of molecular clouds most well-known for the two star-forming clusters NGC1333 and IC348 and the well-studied outflow source in B5. However, when studied at mid- to far-infrared wavelengths the region is dominated by a ∼10pc diameter shell of warm dust, likely generated by an Hii region caused by the early B-star HD278942. Using a revised calibration technique the COMPLETE team has produced high-sensitivity temperature and column-density maps of the Perseus region from IRAS Sky Survey Atlas (ISSA) 60 and 100µm data. In this paper, we combine the ISSA based dust-emission maps with other observations collected

The structure and dynamics of the dense cores in the Perseus molecular cloud complex

We have produced wide-field (≳ 0.1 deg^2) images of the molecular gas around the dense cores observed by Ladd et al. (1994) in the Perseus cloud complex in various CO (CO(1-0), ^(13)CO(1-0), C^(18)O(1-0)) and CS (CS(2-1), C^(34)S(2-1)) isotopomers, and N_2H^+(1-0), using the 16-element focal plane array operating at a wavelength of 3 mm at the Five College Radio Astronomy Observatory. We also performed mosaic observations in the N_2H^+(1-0) line and in the adjacent 3 mm continuum with the OVRO interferometer. Only within one of the observed cores we unambiguously detected a 3 mm continuum compact source with the interferometer. The single-dish large-scale maps of the densest gas, which in Perseus is concentrated within two large filamentary structures roughly aligned along a NE-SW axis, allowed us to analyse the spatial and kinematical properties of the cores and of the surrounding ambient gas. In the PER4/PER5 and PER7 regions we find that the large-scale and core velocity gradients have the same sign and similar magnitudes. In at least three cases we then find pairs of nearby cores with differences in the CS and N_2H^+ emission and in the line profile, which may have been caused by evolutionary effects. The small fraction of cores with compact continuum sources, the chemical differentiation and the inward motions observed suggest that we are observing objects in a phase preceeding the collapse and the formation of stars.

ChandraStudy of Young Stellar Objects in the NGC 1333 Star‐forming Cloud

NGC 1333, a highly active star formation region within the Perseus molecular cloud complex, has been observed with the ACIS-I detector on board the Chandra X-ray Observatory. In our image with a sensitivity limit of ~ 1e28 erg/s, we detect 127 X-ray sources, of which, 95 are known cluster members. The X-ray luminosity function of the discovered YSO population spans a range of 1e28-3.2e31 erg/s in the 0.5-8 keV band. Comparison with K-band source counts indicates that we detect all of the known cluster members with K 12. We detect seven X-ray emitting YSOs which drive optically visible jets as well as one deeply embedded object that has not been detected in near-IR observations. The presence or absence of an outflows does not appear to produce any difference in X-ray properties of YSOs. We also find no systematic differences in X-ray luminosity distributions between two complete subsamples of CTTs and WTTs. That suggests that there is no difference in the astrophysical mechanism of WTT and CTT X-ray emission production. Additional results include: the X-ray emission from two late-B stars which illuminate the reflection nebula originates from unresolved late-type companions; two T Tauri stars are discovered as previously unknown components of visual binaries; and the X-ray counterpart of SVS 16 has the column density much lower than that expected from near-IR photometry and thus its X-ray luminosity is not anomalously high, as has been previously suggested.

The Nature of the [ITAL]IRAS[/ITAL] Ring G159.6−18.5 in Perseus and Its Exciting Star HD 278942

We discuss an extended feature in the Perseus molecular cloud complex, most prominent in the IRAS database as an almost complete ring of radius 0.75 degrees, but also clearly seen in optical surveys and in radio continuum emission.

Protostars in Perseus: Outflow‐induced Fragmentation

We present new far-infrared, submillimeter, and millimeter images of candidate protostars in the Perseus molecular cloud complex: L1448N/IRS3, L1448C, and IRAS 03282+3035. L1448N/IRS3 is now known to comprise three separate millimeter-continuum sources: L1448N(A) and L1448N(B), which form a close (7'' separation) binary, and L1448NW, ~20'' to the northwest. The new maps presented here include 12, 25, 60, and 100 μm high-resolution-processed (HIRES-processed) IRAS images, 450 and 800 μm maps from the 15 m James Clerk Maxwell Telescope (JCMT), and a 1300 μm bolometer array map of the L1448 sources from the IRAM 30 m telescope. We present new spectral energy distributions (SEDs) for L1448C, L1448NW, and IRAS 03282. We confirm the Class 0 status of L1448C, L1448N(A), L1448N(B), and IRAS 03282. There is evidence for a modest compact disk component in L1448C (~0.004 M☉). We deduce that a 1.4 M☉ circumbinary envelope surrounds the ~1 M☉ protobinary system, L1448N(A) + L1448N(B). The dust emission from IRAS 03282 is found to be somewhat extended, on scales of 0.015-0.03 pc. Extensive HIRES-processed point-source modeling of the 100 μm emission associated with IRAS 03282 reveals an elongated structure along a north-south axis, spatially coincident with the previously mapped NH3 (1, 1) emission. Both the 100 μm dust emission and the ammonia trace the dense core from which IRAS 03282 is currently forming. We identify two distinct outflows in L1448N for the first time, one powered by L1448N(A) and the other by L1448N(B). A bridge of dust emission linking L1448C to L1448N is clearly evident in our HIRES-processed 100 μm map. This dust structure traces the surface where the L1448C and L1448N(A) outflows collide. Two new 100 μm emission peaks are found, one coinciding with HH 197, the other with an H2 bow-shock feature. Both 100 μm peaks are located at positions where the blueshifted L1448C jet is deflected. The luminosity radiated by the dust emission bridge is ~6.5 L☉, which is a new estimate for the instantaneous L1448C outflow mechanical luminosity. We find Lmech/Lbol ≥ 50% for all of the confirmed Perseus Class 0 sources for which outflow data are available from the literature. Thus, we confirm a high Lmech/Lbol as a new distinguishing characteristic of Class 0 outflows. The dynamical times for the L1448N(B) and L1448C outflows have been revised upward to 13,000 and 32,000 yr, respectively, based on the identification of L1448N(B) as the powering source of HH 196 and of L1448C as the driving source of HH 267. As a consequence, the outflow dynamical times now agree with the typical ages inferred for Class 0 sources. There is strong evidence for outflow-induced star formation in the L1448 cloud. Being older, the L1448C outflow has disrupted and fragmented the core that is now forming the younger L1448N(A) + L1448N(B) protobinary. The interaction of the L1448N(A) and L1448N(B) outflows, in turn, may have produced the L1448NW condensation.

A Parsec‐Scale Herbig‐Haro Jet in Barnard 5

We report the discovery of a parsec-scale, jetlike, bipolar Herbig-Haro flow, HH 366, emerging from the young stellar object IRS 1, which is embedded in the dark cloud Barnard 5 (B5) at the eastern end of the Perseus molecular cloud complex. The jet is about 22' in extent, which corresponds to a projected length of about 2.2 pc (assuming a distance of 350 pc), and is less than 1' (0.1 pc) wide. The brighter southwestern end of the jet is receding, with a velocity between 30 and 100 km s–1. The fainter eastern lobe is blueshifted with a slightly lower radial velocity amplitude. The blueshifted jet emerges from IRS 1 at a position angle of about 75°. Both the redshifted and blueshifted portions of the flow are brightest at their ends (the most distant points from the source). In the blueshifted eastern lobe, faint emission can be traced to within several arcminutes of the source, while the redshifted lobe emerges from behind the cloud core about 5' southwest of IRS 1.The orientation and kinematics of the Herbig-Haro jet matches that of the inner portion of the CO outflow from IRS 1 mapped at high-angular resolution by Fuller et al. A reanalysis of the Goldsmith et al. 12CO data shows that an envelope of high-velocity molecular gas extends from IRS 1 to both the eastern and western ends of the Herbig-Haro jet. The redshifted lobe of CO emission lying several arc-minutes north of IRS 3 (an infrared source located about 10' to the southwest of IRS 1) coincides with the southwestern (redshifted) optical lobe of the B5 jet. Although previously associated with IRS 3, this lobe is the brightest portion of the southwestern lobe of the IRS 1 CO outflow. Both the CO flow and the HH jet are nearly orthogonal to a 0.06 pc long ridge or extended pseudodisk of dense molecular gas seen in tracers such as HCN. The two lobes of the IRS 1 optical outflow are misaligned; the redshifted lobe appears to be deflected south with respect to the axis inferred by connecting B5 IRS1 to the end of the blueshifted lobe. A roughly 5-10 km s–1 motion of the source with respect to the host cloud could produce this misalignment. The IRS 1 outflow provides evidence for outflow models in which CO is entrained from dense molecular gas by a hypersonic jet.A second Herbig-Haro flow, HH 367, is located 1' southeast (at position angle 155°) of the infrared source B5 IRS 3.

Dense cores in dark clouds. 10: Ammonia emission in the Perseus molecular cloud complex

view Abstract Citations (61) References (56) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Dense Cores in Dark Clouds. X. Ammonia Emission in the Perseus Molecular Cloud Complex Ladd, E. F. ; Myers, P. C. ; Goodman, A. A. Abstract We present a survey for dense material around young IRAS sources in the Perseus molecular cloud complex in the NH3 (J, K)=(1,1) line at 1.3 cm. NH3 emission was detected in eight, and mapped in seven, out of 10 positions chosen for study. The dense cores found typically have lower masses and narrower line widths than cores previously studied in Perseus and are located near sources of lower luminosity. NH3 cores are found throughout the Perseus complex; however, much of the detected dense gas is concentrated into two filamentary 'ridges' located in the western part. As a group, NH3 cores in Perseus have a mean line width of 0.6 km/s, mean radius of 0.12 pc, mean kinetic temperature of 13 K, and mean mass of 9 solar mass. These mean values are larger than the mean values for NH3 cores with associated stars in Taurus, but smaller than the mean values for cores associated with stars in Orion A. Some of the cores in Perseus are 'thermally dominated', with thermal and nonthermal line widths similar to most Taurus cores, while others are 'nonthermally dominated' and are more similar to the cores in Orion A. We conclude that the Perseus complex is intermediate in its star-forming potential between the predominantly low-mass star-producing regions like Taurus and the regions capable of the producing high-mass stars such as Orion A. Publication: The Astrophysical Journal Pub Date: September 1994 DOI: 10.1086/174629 Bibcode: 1994ApJ...433..117L Keywords: Ammonia; Interstellar Gas; Molecular Clouds; Molecular Spectra; Radio Astronomy; Radio Spectra; Sky Surveys (Astronomy); Star Formation; Astronomical Spectroscopy; Emission Spectra; Line Spectra; Stellar Mass; Astronomy; ISM: MOLECULES; ISM: INDIVIDUAL NAME: PERSEUS MOLECULAR CLOUD; RADIO LINES: ISM full text sources ADS | data products SIMBAD (31) Related Materials (12) Part 1: 1983ApJ...264..517M Part 2: 1983ApJ...266..309M Part 3: 1983RMxAA...7..238M Part 4: 1983ApJ...270..105M Part 5: 1983ApJ...270..589B Part 6: 1988ApJ...324..907M Part 7: 1991ApJ...376..561M Part 8: 1992ApJ...384..523F Part 9: 1993ApJ...406..528G Part 10: 1994ApJ...433...96V Part 12: 1998ApJ...506..743B Part 13: 2000ApJ...532.1038V

An infrared survey for embedded young stars in the Perseus molecular cloud complex

view Abstract Citations (65) References (60) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An Infrared Survey for Embedded Young Stars in the Perseus Molecular Cloud Complex Ladd, E. F. ; Lada, E. A. ; Myers, P. C. Abstract We searched the Perseus molecular cloud complex for isolated, embedded, and presumably young stars using the survey data collected with the IRAS and previously published visual extinction data. Of the 23 source positions which satisfied both our IRAS color and visual extinction tests, we imaged 18 and identified the 2 micron counterparts of 11 IRAS sources. We have estimated the luminosities and mean frequencies of these sources and compare these properties with a similarly selected group of sources from the Taurus-Auriga cloud. We find that the isolated sources in Perseus cloud have a slightly higher average luminosity and a distinctly lower average mean frequency than the sources in our Taurus sample. These results suggest that the Perseus cloud is intermediate in its star-forming character between the predominantly low-mass star-forming regions like Taurus and those which are capable of producing very high mass stars, like the clouds in Orion. Publication: The Astrophysical Journal Pub Date: June 1993 DOI: 10.1086/172735 Bibcode: 1993ApJ...410..168L Keywords: Early Stars; Infrared Astronomy; Molecular Clouds; Star Formation; Infrared Astronomy Satellite; Interstellar Extinction; Point Sources; Spectral Energy Distribution; Stellar Luminosity; Astrophysics; INFRARED: STARS; ISM: CLOUDS; STARS: PRE--MAIN-SEQUENCE full text sources ADS | data products SIMBAD (77)