- ID:
- ivo://CDS.VizieR/J/A+A/622/A91
- Title:
- Herschel/HIFI and IRAM 30m images of OMC1
- Short Name:
- J/A+A/622/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young massive stars regulate the physical conditions, ionization, and fate of their natal molecular cloud. It is important to find tracers that help quantifying the stellar feedback processes that take place at different scales. We present ~85arcmin^2^ velocity-resolved maps of several submm molecular lines toward the closest high-mass star-forming region, OMC-1. The observed rotational lines include probes of warm and dense molecular gas that are difficult to detect from ground-based telescopes: CH^+^ (1-0), CO (10-9), HCO^+^ (6-5), and HCN (6-5). These lines trace an extended but thin layer of molecular gas at high thermal pressure, P_th_~10^7^-10^9^K/cm^3^, associated with the FUV-irradiated surface of OMC-1. The intense FUV field, emerging from massive stars in the Trapezium cluster, heats, compresses and photoevaporates the cloud edge. It also triggers the formation of reactive molecules such as CH^+^. The CH^+^ (1-0) emission spatially correlates with the flux of FUV photons impinging the cloud: G_0 from 1e3 to 1e5. This correlation is supported by isobaric PDR models in the parameter space P_th_/G_0_~[5*10^3^-8*10^4^]K/cm^3^ where many PDRs seem to lie. The CH^+^ (1-0) emission correlates with the extended emission from vibrationally excited H_2_, and with that of [CII]158um and CO 10-9, all emerging from FUV-irradiated gas. These correlations link the presence of CH^+^ to the availability of C^+^ ions and of FUV-pumped H_2_(v>0) molecules. The parsec-scale CH^+^ emission and narrow-line (dv~3 km/s) mid-J CO emission arises from extended PDRs and not from fast shocks. PDR line tracers are the smoking gun of the stellar feedback from young massive stars. The PDR component in OMC-1 represents 5 to 10 % of the total gas mass, however, it dominates the emitted line luminosity. These results provide insights into the source of submm CH+ and mid-J CO emission from distant star-forming galaxies.
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- ID:
- ivo://CDS.VizieR/J/A+A/542/A76
- Title:
- Herschel-HIFI water spectra of W43-MM1
- Short Name:
- J/A+A/542/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Herschel/HIFI observations of 14 water lines in W43-MM1, a massive protostellar object in the luminous star-cluster-forming region W43. We place our study in the more general context of high-mass star formation. The dynamics of these regions may be represented by either the monolithic collapse of a turbulent core, or competitive accretion. Water turns out to be a particularly good tracer of the structure and kinematics of the inner regions, allowing an improved description of the physical structure of the massive protostar W43-MM1 and an estimation of the amount of water around it. We analyze the gas dynamics from the line profiles using Herschel-HIFI observations acquired as part of the Water In Star-forming regions with Herschel project of 14 far-IR water lines (H_2_^16^O, H_2_^17^O, H_2_^18^O), CS(11-10), and C^18^O(9-8) lines, using our modeling of the continuum spectral energy distribution. The spectral modeling tools allow us to estimate outflow, infall, and turbulent velocities and molecular abundances. We compare our results to previous studies of low-, intermediate-, and other high-mass objects. As for lower-mass protostellar objects, the molecular line profiles are a mix of emission and absorption, and can be decomposed into 'medium' (full width at half maximum FWHM~=5-10km/s), and 'broad' velocity components (FWHM~=20-35km/s). The broad component is the outflow associated with protostars of all masses. Our modeling shows that the remainder of the water profiles can be well-fitted by an infalling and passively heated envelope, with highly supersonic turbulence varying from 2.2km/s in the inner region to 3.5km/s in the outer envelope. In addition, W43-MM1 has a high accretion rate of between 4.0x10^-4^ and 4.0x10^-2^M_{sun}_/yr, as derived from the fast (0.4-2.9km/s) infall observed. We estimate a lower mass limit for gaseous water of 0.11M_{sun}_ and total water luminosity of 1.5L_{sun}_ (in the 14 lines presented here). The central hot core is detected with a water abundance of 1.4x10^-4^, while the water abundance for the outer envelope is 8x10^-8^. The latter value is higher than in other sources, and most likely related to the high turbulence and the micro-shocks created by its dissipation. Examining the water lines of various energies, we find that the turbulent velocity increases with the distance from the center. While not in clear disagreement with the competitive accretion scenario, this behavior is predicted by the turbulent core model. Moreover, the estimated accretion rate is high enough to overcome the expected radiation pressure.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A90
- Title:
- Herschel/SPIRE spectra in Arp 299
- Short Name:
- J/A+A/568/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Ultra) luminous infrared galaxies ((U)LIRGs) are nearby laboratories that allow us to study similar processes to those occurring in high redshift submillimeter galaxies. Understanding the heating and cooling mechanisms in these galaxies can give us insight into the driving mechanisms in their more distant counterparts. Molecular emission lines play a crucial role in cooling excited gas, and recently, with Herschel Space Observatory we have been able to observe the rich molecular spectrum. Carbon monoxide (CO) is the most abundant and one of the brightest molecules in the Herschel wavelength range. CO transitions from J=4-3 to 13-12 are observed with Herschel, and together, these lines trace the excitation of CO. We study Arp 299, a colliding galaxy group, with one component (A) harboring an active galactic nucleus and two more (B and C) undergoing intense star formation. For Arp 299 A, we present PACS spectrometer observations of high-J CO lines up to J=20-19 and JCMT observations of ^13^CO and HCN to discern between UV heating and alternative heating mechanisms.
- ID:
- ivo://CDS.VizieR/J/A+AS/109/293
- Title:
- Heterochromatic extinction. I.
- Short Name:
- J/A+AS/109/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/426/171
- Title:
- H_2_ flows in rho Ophiuchi A
- Short Name:
- J/A+A/426/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an unbiased search for molecular hydrogen emission in the L1688 cloud within the rho Ophiuchi molecular cloud complex. Our near-infrared survey covers a connected region of extent 35'x35'. We detect several new H_2_ flows but the total number of detected outflows is low and is consistent with the paucity of Class 0 and Class 1 sources in the molecular cloud. From the spatial distribution, their collimation and the individual shapes of the bow shocks, we suggest possible candidates for the outflow sources. Most of the candidate driving sources are deeply embedded in dense cores of the molecular cloud. A very young outflow arises from the newly discovered Class 0 source MMS 126. Two major outflows in the NE-SW direction arise from the YLW 15 and YLW 16 Class I sources. Three additional outflows, which both extend over several arcminutes, arise from the Class I sources YLW 31 and YLW 52. Flow directions are generally NE-SW, perpendicular to the elongation directions of the cloud filaments. The apparent extents of molecular flows are related to either the widths of cloud filaments or to the separation between filaments. The estimated jet power needed to continuously drive and excite the detected portions of the shocked H_2_ outflows lies in the range 0.02-0.2L_{sun}_. Given the critical dependence on the environment, however, the total sizes and powers of the outflows may be considerably larger.
- ID:
- ivo://CDS.VizieR/J/A+A/568/L5
- Title:
- HH 212 CO, CS and 850um ALMA images
- Short Name:
- J/A+A/568/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We wish to exploit the unmatched combination of high angular resolution, high sensitivity, high-imaging fidelity, and spectral coverage provided by ALMA to shed light on the complex kinematics of the innermost central regions of HH212 protostellar system. We mapped the inner 10" (4500AU) of the HH212 system at ~0.5" resolution in several molecular tracers and in the 850um dust continuum using the ALMA interferometer in band 7 in the extended configuration of the Early Science Cycle 0 operations. Within a single ALMA spectral set-up, we simultaneously identify all the crucial ingredients known to be involved in the star formation recipe: (i) the fast, collimated bipolar SiO jet driven by the protostar; (ii) the large-scale swept-up CO outflow; (iii) the flattened rotating and infalling envelope, with bipolar cavities carved by the outflow (in C^17^O(3-2)); and (iv) a rotating wide-angle flow that fills the cavities and surrounds the axial jet (in C^34^S(7-6)). In addition, the compact high-velocity C^17^O emission (+/-1.9-3.5km/s from systemic) shows a velocity gradient along the equatorial plane consistent with a rotating disk of ~0.2"=90AU around a ~0.3+/-0.1M_{sun}_ source. The rotating disk is possibly Keplerian. HH212 is the third Class 0 protostar with possible signatures of a Keplerian disk of radius >=30AU. The warped geometry in our CS data suggests that this large Keplerian disk might result from misaligned magnetic and rotation axes during the collapse phase. The wide-angle CS flow suggests that disk winds may be present in this source.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A82
- Title:
- HH83 outflow spectrally select. structures pm
- Short Name:
- J/A+A/652/A82
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We continue our program of investigation of the proper motions of spectrally separated structures in the Herbig-Haro outflows with the aid of Fabry-Perot scanning interferometry. This work mainly focuses on the physical nature of various structures in the jets. The aim of the present study is to measure the proper motions of the previously discovered kinematically separated structures in the working surface of the HH 83 collimated outflow. We used observations from two epochs separated by 15 years, which were performed on the 6m telescope with Fabry-Perot scanning interferometer. We obtained images corresponding to different radial velocities for the two separate epochs, and used them to measure proper motions. In the course of our data analysis, we discovered a counter bow-shock of HH 83 flow with positive radial velocity, which makes this flow a relatively symmetric bipolar system. The second epoch observations confirm that the working surface of the flow is split into two structures with an exceptionally large (250km/s) difference in radial velocity. The proper motions of these structures are almost equal, which suggests that they are physically connected. The asymmetry of the bow shock and the turning of proper motion vectors suggests a collision between the outflow and a dense cloud. The profile of the H{alpha} line for the directly invisible infrared source HH 83 IRS, obtained by integration of the data within the reflection nebula, suggests it to be of P Cyg type with a broad absorption component characteristic of the FU Ori-like objects. If this object underwent an FU Ori type outburst, which created the HH 83 working surfaces, its eruption took place about 1500 years ago according to the kinematical age of the outflow.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/17
- Title:
- HI and CO observations of M33 interstellar medium
- Short Name:
- J/ApJ/871/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We utilize the multi-wavelength data of M33 to study the origin of turbulence in its interstellar medium. We find that the HI turbulent energy surface density inside 8kpc is ~1-3x10^46^erg/pc^2^, and has no strong dependence on galactocentric radius because of the lack of variation in HI surface density and HI velocity dispersion. Then, we consider the energies injected by supernovae (SNe), the magneto-rotational instability (MRI), and the gravity-driven turbulence from accreted materials as the sources of turbulent energy. For a constant dissipation time of turbulence, the SNe energy can maintain turbulence inside ~4kpc radius (equivalent to ~0.5R_25_), while the MRI energy is always smaller than the turbulent energy within 8kpc radius. However, when we let the dissipation time to be equal to the crossing time of turbulence across the HI scale height, the SNe energy is enough to maintain turbulence out to 7kpc radius, and the sum of SNe and MRI energies is able to maintain turbulence out to 8kpc radius. Due to lack of constraint in the mass accretion rate through the disk of M33, we cannot rule out the accretion driven turbulence as a possible source of energy. Furthermore, by resolving individual giant molecular clouds in M33, we also show that the SNe energy can maintain turbulence within individual molecular clouds with ~1% of coupling efficiency. This result strengthens the proposition that stellar feedback is an important source of energy to maintain turbulence in nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A130
- Title:
- HI and 250um images of the Virgo cirrus
- Short Name:
- J/A+A/597/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the correlation between far-infrared/submm dust emission and atomic gas column density in order to derive the properties of the high Galactic latitude, low density, Milky Way cirrus in the foreground of the Virgo cluster of galaxies. Dust emission maps from 60 to 850um are obtained from SPIRE observations carried out within the Herschel Virgo Cluster Survey, complemented by IRAS-IRIS and Planck-HFI maps. Data from the Arecibo legacy Fast ALFA Survey is used to derive atomic gas column densities for two broad velocity components, low and intermediate velocity clouds. Dust emissivities are derived for each gas component and each far-infrared/submm band. For the low velocity clouds, we measure an average emissivity {epsilon]_{nu}^LVC=(0.79+/-0.08)*10^-20^MJy.cm^2^/sr at 250um. After fitting a modified blackbody to the available bands, we estimated a dust absorption cross-section {tau}_{nu}^LVC/N_HI_=(0.49+/-0.13)*10^-25cm^2^/H at 250um (with dust temperature T=20.4+/-1.5K and spectral index {beta}=1.53+/-0.17). The results are in excellent agreement with those obtained by Planck over a much larger coverage of the high Galactic latitude cirrus (50% of the sky vs 0.2% in our work). For dust associated with intermediate velocity gas, we confirm earlier Planck results and find a higher temperature and lower emissivity and cross-section. After subtracting the modelled components, we find regions at scales smaller than 20' where the residuals deviate significantly from the average, cosmic-infrared-background dominated, scatter. These large residuals are most likely due to local variations in the cirrus dust properties (and/or the dust/atomic-gas correlation) or to high-latitude molecular clouds with average N_H2_<~10^20^cm^-2^. We find no conclusive evidence for intracluster dust emission in Virgo.
- ID:
- ivo://CDS.VizieR/J/ApJ/722/367
- Title:
- HI clouds in Quadrant I of the Milky Way
- Short Name:
- J/ApJ/722/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using 21cm HI observations from the Parkes Radio Telescope's Galactic All-Sky Survey, we measure 255 HI clouds in the lower Galactic halo that are located near the tangent points at 16.9<=l<=35.3{deg} and |b|<~20{deg}. The clouds have a median mass of 700M_{sun}_ and a median distance from the Galactic plane of 660pc.
