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27 papers found.
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A 12CO () and () atlas of circumstellar envelopes of AGB and post-AGB stars

to: R. Neri Such a copious mass loss process necessarily leads to substantial changes in the stellar structure and appearance especially when the amount of mass ejecta becomes comparable to the mass of

A 12CO () and () atlas of circumstellar envelopes of AGB and post-AGB stars

to: R. Neri Such a copious mass loss process necessarily leads to substantial changes in the stellar structure and appearance especially when the amount of mass ejecta becomes comparable to the mass of

Structure and dynamics of the molecular gas in M 2–9: a follow-up study with ALMA

Context. M 2–9 is a young planetary nebula (PN) that shows the characteristics of its last ejections in unprecedented detail. These last ejections are thought to trigger the post−asymptotic giant branch evolution.Aims. To assemble an overall picture of how M 2–9 was shaped, we analyzed the characteristics of the different molecular gas components and their relation with the...

High spatial resolution imaging of SO and H2CO in AB Auriga: The first SO image in a transitional disk

Context. Transitional disks are structures of dust and gas around young stars with large inner cavities in which planet formation may occur. Lopsided dust distributions are observed in the dust continuum emission at millimeter wavelengths. These asymmetrical structures can be explained as being the result of an enhanced gas density vortex where the dust is trapped, potentially...

LkHα 101 at millimeter wavelengths

We present new millimeter observations made with the IRAM interferometer and 30 m telescope of the ionized wind from the massive young stellar object LkHα   101. Several recombination lines, including higher order transitions, were detected for the first time at radio wavelengths in this source. From three α-transitions, we derive an accurate value for the stellar velocity and...

ACA [CI] observations of the starburst galaxy NGC 253

Context. Carbon monoxide (CO) is widely used as a tracer of the molecular gas in almost all types of environments. However, several shortcomings of CO complicate usaging it as H2 tracer, such as its optical depth effects, the dependence of its abundance on metallicity, or its susceptibility to dissociation in highly irradiated regions. Neutral carbon emission has been proposed to...

ALMA reveals the feeding of the Seyfert 1 nucleus in NGC 1566

We report ALMA observations of CO(3–2) emission in the Seyfert 1 galaxy NGC 1566, at a spatial resolution of 25 pc. Our aim is to investigate the morphology and dynamics of the gas inside the central kpc, and to probe nuclear fueling and feedback phenomena. NGC 1566 has a nuclear bar of 1.7 kpc radius and a conspicuous grand design spiral starting from this radius. The ALMA field...

A search for linear polarization in the active galactic nucleus 3C 84 at 239 and 348GHz⋆

We report a search for linear polarization in the active galactic nucleus (AGN) 3C 84 (NGC 1275) at observed frequencies of 239 and 348 GHz, corresponding to rest-frame frequencies of 243 and 354 GHz. We collected polarization data with the IRAM Plateau de Bure Interferometer via Earth rotation polarimetry. We do not detect linear polarization. Our analysis finds 3σ upper limits...

Fueling the central engine of radio galaxies - II. The footprints of AGN feedback on the ISM of 3C 236

Context. There is growing observational evidence of active galactic nuclei (AGN) feedback on the interstellar medium (ISM) of radio-quiet and radio-loud galaxies. While AGN feedback is expected to be more common at high-redshift objects, studying local universe galaxies helps to better characterize the different manifestations of AGN feedback.Aims. Molecular line observations can...

Variations in the fundamental constants in the QSO host J1148+5251 at z = 6.4 and the BR1202−0725 system at z = 4.7

. , Combes F. , 2006 , A&A, 453 , 77 Salome P. , Guelin M. , Downes D. , Cox P. , Guilloteau S. , Omont A. , Gavazzi R. , Neri R. , 2012 , A&A, 545 , A57 Stacey G. J. , Geis N. , Genzel R. , Lugten J. B

Molecular gas in submillimetre-faint, star-forming ultraluminous galaxies at z > 1

We present interferometric CO observations of 12 z∼ 2 submillimetre-faint, star-forming radio galaxies (SFRGs) which are thought to be ultraluminous infrared galaxies (ULIRGs) possibly dominated by warmer dust (Tdust ≳ 40 K) than submillimetre galaxies (SMGs) of similar luminosities. Four other CO-observed SFRGs are included from the literature, and all the observations are taken...

The gain–elevation correction of the IRAM 30–m telescope

The residual surface deformations of an optimized homologous radio reflector produce an elevation dependent gain variation for which astronomical observations must be corrected. For the IRAM 30–m telescope we provide information, and an example, how to correct observations of point–like and extended sources. We find agreement between the gain–elevation dependence predicted from...

High-resolution CO and radio imaging of z ∼ 2 ULIRGs: extended CO structures and implications for the universal star formation law

. Muxlow 4 R. Neri 2 A. Omont 11 0 Institute for Computational Cosmology, Durham University , Durham DH1 3LE 1 Max-Planck Institut fur Extraterrestrische Physik , Giessenbachstrasse 1, D-85741 Garching

A study of the Keplerian accretion disk and precessing outflow in the massive protostar IRAS 20126+4104

We report on interferometric observations at 3.2 and 1.3 mm of the massive young stellar object IRAS 20126+4104 obtained in the C34S and CH3OH lines and in the continuum emission. The C34S data confirm the existence of a Keplerian disk, as already suggested by various authors. However, the mass of the central object is ~7 , significantly less than previous estimates. We believe...

Detection of two massive CO systems in 4C 41.17 at z = 3.8

We have detected CO(4-3) in the radio galaxy 4C 41.17 with the IRAM Interferometer. The CO is in two massive () systems separated by 18 (13 kpc), and by 400 in velocity, which coincide with two different dark lanes in a deep Lyα image. One CO component coincides with the cm-radio core of the radio galaxy, and its redshift is close to that of the  λ 1640 AGN line. The second CO...

New light on the S235A-B star forming region

The S235A-B star forming region has been extensively observed in the past from the radio to the near IR, but what was happening in the immediate surroundings of the water maser, placed in between the two nebulosities, was still unclear because of insufficient resolution especially in the spectral range from the Far IR to the mm, even though there were sound indications that new...

The properties of the interstellar medium within a star-forming galaxy at z= 2.3

. Neri 1 B. Oca na Flaquer 10 0 Max-Planck-Institut fu r Radioastronomie , Auf dem Hu gel 69, 53121 Bonn , Germany 1 Institut de Radio Astronomic Millimetrique , 300 rue de la Piscine, Domaine

A study of the gas–star formation relation over cosmic time*

We use the first systematic data sets of CO molecular line emission in z∼ 1–3 normal star-forming galaxies (SFGs) for a comparison of the dependence of galaxy-averaged star formation rates on molecular gas masses at low and high redshifts, and in different galactic environments. Although the current high-z samples are still small and biased towards the luminous and massive tail...