R. Aladro

THE 2014 ALMA LONG BASELINE CAMPAIGN: FIRST RESULTS FROM HIGH ANGULAR RESOLUTION OBSERVATIONS TOWARD THE HL TAU REGION

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0. ′′ 075 (10 AU) to 0. ′′ 025 (3.5 AU), revealing an astonishing level of detail in the cir cumstellar disk surrounding the young solar analogue HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination (46.72 ◦ ± 0.05 ◦ ) and position angle (+138.02 ◦ ± 0.07 ◦ ). We obtain a high-fidelity image of the 1.0 mm spectral index (�), which ranges from � � 2.0 in the optically-thick central peak and two brightest ring s, increasing to 2.3-3.0 in the dark rings. The dark rings are not devoid of emission, and we estimate a grain emissivity index of 0.8 for the innermost dark ring and lower for subsequent dark rings, consistent with some degree of grain growth and evolution. Additional clues that the rings arise from planet formation incl ude an increase in their central offsets with radius and the presence of numerous orbital resonances. At a resolution of 35 AU, we resolve the molecular component of the disk in HCO + (1-0) which exhibits a pattern over LSR velocities from 2-12 km s -1 consistent with Keplerian motion around a �1.3M⊙ star, although complicated by absorption at low blue-shifted velocities. We also serendipitously detect and resolve the nearby protost ars XZ Tau (A/B) and LkH�358 at 2.9 mm. Subject headings: stars: individual (HL Tau, XZ Tau, LkH�358) — protoplanetary disks — stars: formation — submillimeter: planetary systems — techniques: interferometric

The 2014 ALMA Long Baseline Campaign : Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z = 3.042

We present initial results of very high resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations of the

Carbon and oxygen isotope ratios in starburst galaxies: New data from NGC 253 and Mrk 231 and their implications

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Multimolecule ALMA observations toward the Seyfert 1 galaxy NGC 1097

=3.042 gravitationally lensed galaxy HATLAS J090311.6+003906 (SDP.81). These observations were carried out using a very extended configuration as part of Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines of up to 15 km. We present continuum imaging at 151, 236 and 290 GHz, at unprecedented angular resolutions as fine as 23 milliarcseconds (mas), corresponding to an un-magnified spatial scale of ~180 pc at z=3.042. The ALMA images clearly show two main gravitational arc components of an Einstein ring, with emission tracing a radius of ~1.5. We also present imaging of CO(10-9), CO(8-7), CO(5-4) and H2O line emission. The CO emission, at an angular resolution of ~170 mas, is found to broadly trace the gravitational arc structures but with differing morphologies between the CO transitions and compared to the dust continuum. Our detection of H2O line emission, using only the shortest baselines, provides the most resolved detection to date of thermal H2O emission in an extragalactic source. The ALMA continuum and spectral line fluxes are consistent with previous Plateau de Bure Interferometer and Submillimeter Array observations despite the impressive increase in angular resolution. Finally, we detect weak unresolved continuum emission from a position that is spatially coincident with the center of the lens, with a spectral index that is consistent with emission from the core of the foreground lensing galaxy.

CS, HC3N, and CH3CCH multi-line analyses toward starburst galaxies - The evolution of cloud structures in the central regions of galaxies

Carbon and oxygen isotope ratios are excellent measures of nuclear processing, but few such data have been taken toward extragalactic targets so far. Therefore, using the IRAM 30-m telescope, CN and CO isotopologues have been measured toward the nearby starburst galaxy NGC 253 and the prototypical ultraluminous infrared galaxy Mrk 231. Toward the center of NGC 253, the CN and (CN)-C-13 N = 1 -> 0 lines indicate no significant deviations from expected local thermodynamical equilibrium after accounting for moderate saturation effects (10 and 25%) in the two detected spectral components of the main species. Including calibration uncertainties, which dominate the error budget, the C-12/C-13 ratio becomes 40 +/- 10. This is larger than the ratio in the central molecular zone of the Galaxy, suggesting a higher infall rate of poorly processed gas toward the central region. Assuming that the ratio also holds for the CO emitting gas, this yields O-16/O-18 = 145 +/- 36 and O-16/O-17 = 1290 +/- 365 and a S-32/S-34 ratio close to the one measured for the local interstellar medium (2025). No indication of vibrationally excited CN is found in the lower frequency fine structure components of the N = 1 -> 0 and 2 -> 1 transitions at rms noise levels of 3 and 4 mK (15 and 20 mJy) in 8.5 km s-1 wide channels. Peak line intensity ratios between NGC 253 and Mrk 231 are similar to 100 for (CO)-C-12-O-16 and (CO)-C-12-O-18 J = 1 -> 0, while the ratio for (CO)-C-13-O-16 J = 1 -> 0 is similar to 250. This and similar (CO)-C-13 and (CO)-O-18 line intensities in the J = 1 -> 0 and 2 -> 1 transitions of Mrk 231 suggest C-12/C-13 similar to 100 and O-16/O-18 similar to 100, in agreement with values obtained for the less evolved ultraluminous merger Arp 220. Also, when accounting for other (scarcely available) extragalactic data, C-12/C-13 ratios appear to vary over a full order of magnitude, from >100 in ultraluminous high redshift galaxies to similar to 100 in more local such galaxies to similar to 40 in weaker starbursts that are not undergoing a large scale merger to 25 in the central molecular zone of the Milky Way. With C-12 being predominantly synthesized in massive stars, while C-13 is mostly ejected by longer lived lower mass stars at later times, this is qualitatively consistent with our results of decreasing carbon isotope ratios with time and rising metallicity. It is emphasized, however, that both infall of poorly processed material, initiating a nuclear starburst, and the ejecta from newly formed massive stars (in particular in the case of a top-heavy stellar initial mass function) can raise the carbon isotope ratio for a limited amount of time.

Lambda = 3 mm line survey of nearby active galaxies

Context. The nearby Sy 1 galaxy NGC 1097 represents an ideal laboratory for exploring the molecular chemistry in the surroundings of an active galactic nucleus (AGN). Aims. Exploring the distribution of di erent molecular species allows us to understand the physical processes a ecting the interstellar medium both in the AGN vicinity and in the outer star forming molecular ring. Methods. We carried out 3 mm ALMA observations that include seven di erent molecular species, namely HCN, HCO + , CCH, CS, HNCO, SiO, HC3N, and SO, as well as the 13 C isotopologues of the first two. Spectra were extracted from selected positions and all species were imaged over the central 2 kpc ( 30 00 ) of the galaxy at a resolution of 2.2 00 1:5 00 (150 pc 100 pc). Results. HCO + and CS appear to be slightly enhanced in the star forming ring. CCH shows the largest variations across NGC 1097 and is suggested to be a good tracer of both obscured and early stage star formation. HNCO, SiO, and HC3N are significantly enhanced in the inner circumnuclear disk surrounding the AGN. Conclusions. Di erences in the molecular abundances are observed between the star forming ring and the inner circumnuclear disk. We conclude that the HCN/HCO + and HCN/CS di erences observed between AGN-dominated and starburst (SB) galaxies are not due to a HCN enhancement due to X-rays, but rather this enhancement is produced by shocked material at distances of 200 pc from the AGN. Additionally, we claim that lower HCN/CS is a combination of a small underabundance of CS in AGNs, together with excitation e ects, where a high density gas component ( 10 6 cm 3 ) may be more prominent in SB galaxies. However, the most promising are the di erences found among the dense gas tracers that, at our modest spatial resolution, seem to outline the physical structure of the molecular disk around the AGN. In this picture, HNCO probes the well-shielded gas in the disk, surrounding the dense material moderately exposed to the X-ray radiation traced by HC3N. Finally SiO might be the innermost molecule in the disk structure.

The unbearable opaqueness of Arp220

Aims. We aim to study the properties of the dense molecular gas towards the inner few 100 pc of four nearby starburst galaxies dominated both by photo dissociation regions (M 82) and large-scale shocks (NGC 253, IC 342, and Maffei 2), and to connect the chemical and physical properties of the molecular clouds with the evolutionary stage of the nuclear starbursts. Methods. We have carried out multi-transitional observations and analyses of three dense gas molecular tracers, CS, HC3N (cyanoacetylene), and CH3CCH (methyl acetylene), using Boltzmann diagrams in order to determine the rotational temperatures and column densities of the dense gas, and using a large velocity gradients model to calculate the H2 density structure in the molecular clouds. Results. The CS and HC3N data indicate the presence of density gradients in the molecular clouds. These two molecules show similar excitation conditions, suggesting that they arise from the same gas components. In M 82, CH3CCH has the highest fractional abundance determined in an extragalactic source (1.1 × 10 −8 ). Conclusions. The density and the chemical gradients we found in all galaxies can be explained in the framework of the starburst evolution, which affects the chemistry and the structure of molecular clouds around the galactic nuclei. The young shock-dominated starburst galaxies, like presumably Maffei 2, show a cloud structure with a fairly uniform density and chemical composition that suggests low star formation activity. Molecular clouds in galaxies with starburst in an intermediate stage of evolution, such as NGC 253 and IC 342, show clouds with a high density contrast (two orders of magnitude) between the denser regions (cores) and the less dense regions (halos) of the molecular clouds and relatively constant chemical abundance. Finally, the galaxy with the most evolved starburst, M 82, has clouds with a fairly uniform density structure, large envelopes of atomic/molecular gas subjected to UV photodissociating radiation from young star clusters, and very different chemical abundances of HC3 Na nd CH 3CCH.

Chemical features in the circumnuclear disk of the Galactic center

We used the IRAM 30m telescope to observe the frequency range [86-116]GHz towards the central regions of the starburst galaxies M83, M82, and NGC253, the AGNs M51, NGC1068, and NGC7469, and the ULIRGs Arp220 and Mrk231. Assuming LTE conditions, we calculated the column densities of 27 molecules and 10 isotopologues. Among others, we report the first tentative detections of CH3CHO, HNCO, and NS in M82 and, for the first time in the extragalactic medium, HC5N in NGC253. Halpha recombination lines were only found in M82 and NGC253. Vibrationally excited lines of HC3N were only detected in Arp220. CH3CCH emission is only seen in the starburst-dominated galaxies. By comparison of the fractional abundances among the galaxies, we looked for the molecules that are best suited to characterise the chemistry of starbursts, AGNs and ULIRGs, as well as the differences among galaxies within the same group.

Water, methanol and dense gas tracers in the local ULIRG Arp 220: results from the new SEPIA Band 5 Science Verification campaign

We explore the potential of imaging vibrationally excited molecular emission at high angular resolution to better understand the morphology and physical structure of the dense gas in Arp~220 and to gain insight into the nature of the nuclear powering sources. Vibrationally excited emission of HCN is detected in both nuclei with a very high ratio relative to the total

Chemistry in isolation: High CCH/HCO+ line ratio in the AMIGA galaxy CIG 638

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