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High-Velocity Clouds (HVCs) have radial velocities that cannot be explained by the global Galactic rotation; their distances remain mostly unknown, and their true nature and origin are still a mystery. Some of them could be of galactic…

Astrophysics · Physics 2007-05-23 F. Combes , V. Charmandaris

Resolved molecular line observations are essential for gaining insight into the physical and chemical structure of protoplanetary disks, particularly in cold, dense regions where planets form and acquire their chemical compositions.…

We measure the CO-to-H$_2$ conversion factor ($\alpha_\mathrm{CO}$) in 37 galaxies at 2~kpc resolution, using dust surface density inferred from far-infrared emission as a tracer of the gas surface density and assuming a constant…

We present the results of a search for cold gas at high redshift along QSO lines-of-sight carried out without any a priori assumption on the neutral atomic-hydrogen (HI) content of the absorbers. To do this, we systematically looked for…

Astrophysics of Galaxies · Physics 2015-07-22 C. Ledoux , P. Noterdaeme , P. Petitjean , R. Srianand

We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6 and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption…

Astrophysics of Galaxies · Physics 2015-12-16 Ryo Ando , Kotaro Kohno , Yoichi Tamura , Takuma Izumi , Hideki Umehata , Hiroshi Nagai

Using the Atacama Large Millimeter/sub-millimeter Array, we have detected CO(3-2) line and far-infrared continuum emission from a galaxy associated with a high-metallicity ([M/H] = -0.27) damped Ly-alpha absorber (DLA) at z =2.19289. The…

We report new near-infrared and mm-wave observational data on a selection of massive Galactic molecular clumps (part of the CHaMP sample) and their associated young star clusters. The clumps show, for the first time in a "dense gas tracer",…

We investigate interstellar absorption from molecular hydrogen (H_2) and metals in an intermediate-velocity cloud (IVC) in the direction of the LMC star Sk -68 80 (HD 36521), based on data from the Far Ultraviolet Spectroscopic Explorer…

Astrophysics · Physics 2011-05-23 P. Richter , K. R. Sembach , J. C. Howk

The factor relating CO emission to molecular hydrogen column density, XCO, is still subject to uncertainty, in particular at low metallicity. Here, to quantify XCO at two different spatial resolutions, we exploit a dust-based method…

Absorption in the J{K-K+} = 2{11}-2{12} transition of formaldehyde at 2 cm towards the ultracompact HII regions C1 and C2 of W 58 has been observed with the VLA with an angular resolution of ~0.2'' and a velocity resolution of ~1 km/s. The…

Astrophysics · Physics 2009-10-31 H. R. Dickel , W. M. Goss , C. G. De Pree

Observations of various molecular lines toward a disk region of a nearby galaxy are now feasible, and they are being employed as diagnostic tools to study star-formation activities there. However, the spatial resolution attainable for a…

Astrophysics of Galaxies · Physics 2019-07-17 Yuri Nishimura , Yoshimasa Watanabe , Nanase Harada , Kotaro Kohno , Satoshi Yamamoto

Determining the locations of the major snowlines in protostellar environments is crucial to fully understand the planet formation process and its outcome. Despite being located far enough from the central star to be spatially resolved with…

Solar and Stellar Astrophysics · Physics 2018-09-12 Merel L. R. van 't Hoff

We present large scale observations of C18O(1-0) towards four massive star forming regions for MON R2, S156, DR17/L906 and M17/M18. The transitions of H2CO(110-111), C18O(1-0) and 6 cm continuum were compared towards the four regions.…

Solar and Stellar Astrophysics · Physics 2015-06-18 Xin. Di. Tang , Jarken Esimbek , Jian Jun Zhou , Gang. Wu , Daniel Okoh

We present here the first results from a high-resolution survey of the 12CO(J=1-0) emission across the northern part of the poorly-enriched Small Magellanic Cloud, made with the ATNF Mopra telescope. Three molecular complexes detected in…

Astrophysics of Galaxies · Physics 2015-05-18 E. Muller , J. Ott , A. Hughes , J. Pineda , T. Wong , N. Mizuno , A. Kawamura , Y. Mizuno , Y. Fukui , T. Onishi , M. Rubio

We present the detection analysis of a diffuse molecular cloud at z$_{abs}$=2.4636 towards the quasar SDSS J1513+0352(z$_{em}\,\simeq$ 2.68) observed with the X-shooter spectrograph(VLT). We measure very high column densities of atomic and…

We present the results of ALMA $\sim$2 mm, $\lesssim$1$''$-resolution observations of ten (ultra)luminous infrared galaxies ([U]LIRGs; infrared luminosity $\gtrsim$ 10$^{11.7}$L$_{\odot}$) at $z <$ 0.15, targeting dense ($>$10$^{4}$…

Astrophysics of Galaxies · Physics 2022-03-02 Masatoshi Imanishi , Kouichiro Nakanishi , Takuma Izumi , Shunsuke Baba

We have mapped HCN and HCO$^{+}$ (J = 1 $\to$ 0) line emission toward a sample of seven star-forming regions (with 12 + log[O/H] range from 8.34 to 8.69) in the outer Milky Way (Galactocentric distance > 9.5 kpc), using the 14-meter radio…

Astrophysics of Galaxies · Physics 2022-09-14 Sudeshna Patra , Neal J. Evans , Kee-Tae Kim , Mark Heyer , Jens Kauffmann , Jessy Jose , Manash R. Samal , Swagat R. Das

Proximate molecular quasar absorbers (PH2) are an intriguing population of absorption systems recently uncovered through strong H2 absorption at small velocity separation from the background quasars. We performed a multi-wavelength…

Astrophysics of Galaxies · Physics 2023-05-10 P. Noterdaeme , S. Balashev , R. Cuellar , J. -K. Krogager , F. Combes , A. De Cia , N. Gupta , C. Ledoux , S. López , R. Srianand

Stars form out of the densest parts of molecular clouds. Far-IR emission can be used to estimate the Star Formation Rate (SFR) and high dipole moment molecules, typically HCN, trace the dense gas. A strong correlation exists between HCN and…

Astrophysics of Galaxies · Physics 2016-12-28 J. Braine , Y. Shimajiri , P. André , S. Bontemps , Yu Gao , Hao Chen , C. Kramer

(Abridged) We present the results of a systematic GBT and GMRT survey for 21-cm absorption in a sample of 10 DLAs at 2<z_abs<3.4. Analysis of L-band VLBA images of the background QSOs are also presented. We detect 21-cm absorption in only…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 R. Srianand , N. Gupta , P. Petitjean , P. Noterdaeme , C. Ledoux , C. J. Salter , D. J. Saikia