- ID:
- ivo://CDS.VizieR/J/A+A/617/A27
- Title:
- Kinematics of dense gas in L1495 filament
- Short Name:
- J/A+A/617/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nitrogen bearing species, such as NH_3_, N_2_H^+^, and their deuterated isotopolo- gues show enhanced abundances in CO-depleted gas, and thus are perfect tracers of dense and cold gas in star-forming regions. The Taurus molecular cloud contains the long L1495 filament providing an excellent opportunity to study the process of star formation in filamentary environments. We study the kinematics of the dense gas of starless and protostellar cores traced by the N_2_D^+^(2-1), N_2_H^+^(1-0), DCO^+^(2-1), and H^13^CO^+^(1-0) transitions along the L1495 filament and the kinematic links between the cores and surrounding molecular cloud. We measured velocity dispersions, local and total velocity gradients, and estimate the specific angular momenta of 13 dense cores in the four transitions using on-the-fly observations with the IRAM 30-m antenna. To study a possible connection to the filament gas, we used the C^18^O(1-0) observations.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/644/A10
- Title:
- LARS XI. Turbulence Driven Lyman Alpha Escape
- Short Name:
- J/A+A/644/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the global dust and (molecular) gas content in the Lyman Alpha Reference Sample (LARS), i.e. 14 local star-forming galaxies. We characterize their interstellar medium and relate newly derived properties to quantities relevant for Ly{alpha} escape. We observed LARS galaxies with Herschel/PACS, SOFIA/FIFI-LS, the IRAM 30m telescope and APEX, targeting far-infrared (FIR) continuum and emission lines of [CII]158um, [OI]63um, [OIII]88um and low-J CO lines. Using Bayesian methods we derive dust model parameters and estimate total gas masses for all LARS galaxies, taking into account a metallicity-dependent gas-to-dust ratio. Star formation rates were estimated from FIR, [CII]158um and [OI]63um luminosities. LARS covers a wide dynamic range in the derived properties, with FIR-based star formation rates from ~0.5-100M_{sun}/yr, gas fractions between ~15-80% and gas depletion times ranging from a few hundred Myr up to more than 10Gyr. The distribution of LARS galaxies in the {SIGMA}_gas_ vs. {SIGMA}_SFR_ (Kennicutt-Schmidt plane) is thus quite heterogeneous. However, we find that LARS galaxies with the longest gas depletion times, i.e. relatively high gas surface densities ({SIGMA}_gas_) and low star formation rate densities ({SIGMA}_SFR_ have by far the highest Ly{alpha} escape fraction. A strong [Math Processing Error]linear relation is found between Ly{alpha} escape fraction and the total gas (HI+H_2_) depletion time. We argue that the Ly{alpha} escape in those galaxies is driven by turbulence in the star-forming gas that shifts the Ly{alpha} photons out of resonance close to the places where they originate. We further report on an extreme [CII]158um excess in LARS 5, corresponding to ~14+/-3% of the FIR luminosity, i.e. the most extreme [CII]-to-FIR ratio observed in a non-AGN galaxy to date.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A20
- Title:
- L1157-B1 DCN (2-1) and H^13^CN (2-1) datacubes
- Short Name:
- J/A+A/604/A20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed high-angular-resolution observations toward L1157-B1 with the IRAM NOEMA interferometer of the DCN (2-1) and H^13^CN (2-1) lines to compute the deuterated fraction, D_frac_(HCN), and compare it with previously reported D_frac_ of other molecular species. Our aim is to observationally investigate the role of the different chemical processes at work that lead to formation of the DCN and compare it with HDCO, the two deuterated molecules imaged with an interferometer, and test the predictions of the chemical models for their formation.
- ID:
- ivo://CDS.VizieR/J/AJ/160/103
- Title:
- MACS J1447.4+0827 multiwavelength study
- Short Name:
- J/AJ/160/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Clusters of galaxies are outstanding laboratories for understanding the physics of supermassive black hole (SMBH) feedback. Here we present the first Chandra, Karl G. Jansky Very Large Array, and Hubble Space Telescope analysis of MACS J1447.4+0827 (z=0.3755), one of the strongest cool core clusters known, in which extreme feedback from its central SMBH is needed to prevent the hot intracluster gas from cooling. Using this multiwavelength approach, including 70ks of Chandra X-ray observations, we detect the presence of collimated jetted outflows that coincide with a southern and a northern X-ray cavity. The total mechanical power associated with these outflows (P_cav_~6x1044erg/s) is roughly consistent with the energy required to prevent catastrophic cooling of the hot intracluster gas (L_cool_=1.71{+/-}0.01x1045erg/s for t_cool_=7.7Gyr), implying that powerful SMBH feedback was in place several Gyr ago in MACS J1447.7+0827. In addition, we detect the presence of a radio minihalo that extends over 300kpc in diameter (P1.4GHz=3.0{+/-}0.3x1024W/Hz). The X-ray observations also reveal an ~20kpc plumelike structure that coincides with optical dusty filaments that surround the central galaxy. Overall, this study demonstrates that the various physical phenomena occurring in the most nearby clusters of galaxies are also occurring in their more distant analogs.
- ID:
- ivo://CDS.VizieR/J/ApJ/845/116
- Title:
- Mapping spectral line survey toward W51 in 3mm
- Short Name:
- J/ApJ/845/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a mapping spectral line survey toward the Galactic giant molecular cloud W51 in the 3mm band with the Mopra 22m telescope in order to study an averaged chemical composition of the gas extended over a molecular-cloud scale in our Galaxy. We have observed the area of 25'x30', which corresponds to 39pcx47pc. The frequency ranges of the observation are 85.1-101.1GHz and 107.0-114.9GHz. In the spectrum spatially averaged over the observed area, spectral lines of 12 molecular species and 4 additional isotopologues are identified. An intensity pattern of the spatially averaged spectrum is found to be similar to that of the spiral arm in the external galaxy M51, indicating that these two sources have similar chemical compositions. The observed area has been classified into five subregions according to the integrated intensity of ^13^CO(J=1-0) (I_13CO_), and contributions of the fluxes of 11 molecular lines from each subregion to the averaged spectrum have been evaluated. For most of the molecular species, 50% or more of the flux comes from the subregions with I_13CO_ from 25 to 100K.km.s^-1^, which does not involve active star-forming regions. Therefore, the molecular-cloud-scale spectrum observed in the 3mm band hardly represents the chemical composition of star-forming cores, but mainly represents the chemical composition of an extended quiescent molecular gas. The present result constitutes a sound base for interpreting the spectra of external galaxies at a resolution of a molecular-cloud scale (~10pc) or larger.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/46
- Title:
- methoxy radical (CH_3_O) rotational spectrum
- Short Name:
- J/ApJ/835/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The methoxy radical (CH_3_O) has recently been detected in the interstellar medium and may be an important tracer of methanol-related chemistry in cold sources. Despite its importance, the spectral information needed to guide further astronomical searches is limited. We have therefore studied the low-temperature rotational spectrum in the laboratory within the spectral range of 246-303GHz. We have combined these new measurements with results from a number of literature reports to refine the molecular parameters and provide an updated and improved spectral line catalog. We present here the results of the laboratory studies and the refined analysis for the millimeter and submillimeter spectrum of methoxy.
- ID:
- ivo://CDS.VizieR/J/A+A/553/A115
- Title:
- Millimetric and far-IR maps of IRDC 18310-4
- Short Name:
- J/A+A/553/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Because of their short evolutionary time-scales, the earliest stages of high-mass star formation prior to the existence of any embedded heating source have barely been characterized until today. We study the fragmentation and dynamical properties of a massive starless gas clump at the onset of high-mass star formation. Based on Herschel continuum data we identify a massive gas clump that remains far-infrared dark up to 100um wavelengths. The fragmentation and dynamical properties are investigated by means of Plateau de Bure Interferometer and Nobeyama 45m single-dish spectral line and continuum observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/1
- Title:
- 1mm spectral line survey toward GLIMPSE EGOs
- Short Name:
- J/ApJS/202/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A northern subsample of 89 Spitzer GLIMPSE extended green objects (EGOs), the candidate massive young stellar objects, are surveyed for molecular lines in two 1GHz ranges: 251.5-252.5 and 260.188-261.188GHz. A comprehensive catalog of observed molecular line data and spectral plots are presented. Eight molecular species are undoubtedly detected: H^13^CO^+^, SiO, SO, CH_3_OH, CH_3_OCH_3_, CH_3_CH_2_CN, HCOOCH_3_, and HN^13^C. The H^13^CO^+^ 3-2 line is detected in 70 EGOs, among which 37 also show the SiO 6-5 line, demonstrating their association with dense gas and supporting the outflow interpretation of the extended 4.5um excess emission. Our major dense gas and outflow tracers (H^13^CO^+^, SiO, SO, and CH_3_OH) are combined with our previous survey of ^13^CO, ^12^CO, and C^18^O 1-0 toward the same sample of EGOs for a multi-line, multi-cloud analysis of linewidth and luminosity correlations.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/348
- Title:
- 1mm spectral survey of IRC+10216 & VY CMa
- Short Name:
- J/ApJS/190/348
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A low noise (1{sigma}rms~3mK) 1mm spectral survey (214.5-285.5GHz) of the oxygen-rich supergiant VY Canis Majoris and the carbon-rich asymptotic giant branch star IRC +10216 has been conducted using the Arizona Radio Observatory's 10m Submillimeter Telescope. Here the complete data set is presented. This study, carried out with a new ALMA-type receiver, marks the first continuous band scan of an O-rich circumstellar envelope, and the most sensitive survey to date of IRC+10216. In VY CMa, 130 distinct molecular lines were detected, 14 of which cannot be identified; in IRC +10216, 717 lines were observed, with 126 features remaining unidentified. In the 1mm bands of VY CMa and IRC +10216, emission is present from 18 and 32 different chemical compounds, respectively, with 10 species common to both sources. Many narrow emission lines were observed in both circumstellar shells, arising from vibrationally excited molecules and from refractory-containing species. Line profiles in VY CMa also exhibit a variety of different shapes, caused by the complex, asymmetric outflow of this object.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A48
- Title:
- Mm-spectra of comets C/2001 Q2 and C/2002 T7
- Short Name:
- J/A+A/559/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemical composition of comets can be inferred using spectroscopic observations in submillimeter and radio wavelengths. We aim to compare the production rates ratio of several volatiles in two comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), which are generally regarded as dynamically new comets likely to originate in the Oort cloud. This type of comets is considered to be composed of primitive material that has not undergone considerable thermal processing. The line emission in the coma was measured in the comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7-11 May 2004, at heliocentric distances of 1.0 and 0.7AU, respectively, by means of high resolution spectroscopic observations using the 10-m Submillimeter Telescope (SMT) at the Arizona Radio Observatory (ARO). Both objects became very bright and reached naked-eye visibility during their perihelion passage in the spring of 2004.
