- ID:
- ivo://CDS.VizieR/J/PASJ/63/S379
- Title:
- MOIRCS Deep Survey deep and wide catalogs
- Short Name:
- J/PASJ/63/S379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep J-, H-, and Ks-band imaging data of the MOIRCS Deep Survey (MODS), which was carried out with the Multi-Object Infrared Camera and Spectrograph (MOIRCS) mounted on the Subaru Telescope in the GOODS-North region. The data reach 5{sigma} total limiting magnitudes for point sources of J=23.9, H=22.8, and Ks=22.8 (Vega magnitude) over 103 arcmin^2^ (wide field). In 28 arcmin^2^ of the survey area, which is an ultra-deep field of the MODS (deep field), the data reach 5{sigma} depths of J=24.8, H=23.4, and Ks=23.8. The spatial resolutions of the combined images are FWHM~0.6" and ~0.5" for the wide and deep fields in all bands, respectively. Combining the MODS data with the multi-wavelength public data taken with the HST, Spitzer, and other ground-based telescopes in the GOODS field, we constructed a multi-wavelength photometric catalog of Ks-selected sources.
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2342. MOIRCS Deep Survey. VII.
- ID:
- ivo://CDS.VizieR/J/PASJ/63/S363
- Title:
- MOIRCS Deep Survey. VII.
- Short Name:
- J/PASJ/63/S363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigated rest-frame near-infrared (NIR) morphologies of a sample of 139 galaxies with Ms>=1x10^109M_{sun}_ at z=0.8-1.2 in the GOODS-North field using our deep NIR imaging data (MOIRCS Deep Survey, MODS). We focused on Luminous Infrared Galaxies (LIRGs), which dominate a high star formation rate (SFR) density at z~1, in a sample identified by cross-correlating with the Spitzer/MIPS 24mum source catalog. We performed two-dimensional light profile fittings of z~1 galaxies in the Ks-band (rest-frame J-band) with a single-component Sersic model.
- ID:
- ivo://CDS.VizieR/J/AJ/147/143
- Title:
- MOJAVE. XI. Spectral distributions
- Short Name:
- J/AJ/147/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained milliarcsecond-scale spectral index distributions for a sample of 190 extragalactic radio jets through the Monitoring of Jets in Active Galactic Nuclei with the VLBA Experiments (MOJAVE) project. The sources were observed in 2006 at 8.1, 8.4, 12.1, and 15.4GHz, and we have determined spectral index maps between 8.1 and 15.4GHz to study the four-frequency spectrum in individual jet features. We have performed detailed simulations to study the effects of image alignment and (u, v)-plane coverage on the spectral index maps to verify our results. We use the spectral index maps to study the spectral index evolution along the jet and determine the spectral distributions in different locations of the jets. The core spectral indices are on average flat with a mean value of +0.22+/-0.03 for the sample, while the jet spectrum is in general steep with a mean index of -1.04+/-0.03. A simple power-law fit is often inadequate for the core regions, as expected if the cores are partially self-absorbed. The overall jet spectrum steepens at a rate of about -0.001 to -0.004 per deprojected parsec when moving further out from the core with flat spectrum radio quasars having significantly steeper spectra (mean -1.09+/-0.04) than the BL Lac objects (mean -0.80+/-0.05). However, the spectrum in both types of objects flattens on average by ~0.2 at the locations of the jet components indicating particle acceleration or density enhancements along the jet. The mean spectral index at the component locations of -0.81+/-0.02 corresponds to a power-law index of ~2.6 for the electron energy distribution. We find a significant trend that jet components with linear polarization parallel to the jet (magnetic field perpendicular to the jet) have flatter spectra, as expected for transverse shocks. Compared to quasars, BL Lacs have more jet components with perpendicular magnetic field alignment, which may explain their generally flatter spectra. The overall steepening of the spectra with distance can be explained with radiative losses if the jets are collimating or with the evolution of the high-energy cutoff in the electron spectrum if the jets are conical. This interpretation is supported by a significant correlation with the age of the component and the spectral index, with older components having steeper spectra.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/4992
- Title:
- MOJAVE XIV. AGN jet shapes & opening angles
- Short Name:
- J/MNRAS/468/4992
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 15 GHz stacked VLBA images of 373 jets associated with active galactic nuclei (AGN) having at least 5 observing epochs within a 20yr time interval 1994-2015 from the MOJAVE programme and/or its precursor, the 2 cm VLBA Survey. These data are supplemented by 1.4 GHz single-epoch VLBA observations of 135 MOJAVE AGNs to probe larger scale jet structures. The typical jet geometry is found to be close to conical on scales from hundreds to thousands of parsecs, while a number of galaxies show quasi-parabolic streamlines on smaller scales. A true jet geometry in a considerable fraction of AGNs appears only after stacking epochs over several years. The jets with significant radial accelerated motion undergo more active collimation. We have analyzed total intensity jet profiles transverse to the local jet ridgeline and derived both apparent and intrinsic opening angles of the flows, with medians of 21.5{deg} and 1.3{deg}, respectively. The Fermi LAT-detected gamma-ray AGNs in our sample have, on average, wider apparent and narrower intrinsic opening angle, and smaller viewing angle than non LAT-detected AGNs. We have established a highly significant correlation between the apparent opening angle and gamma-ray luminosity, driven by Doppler beaming and projection effects.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/43
- Title:
- MOJAVE. XVII. Parsec-scale jet kinematics of AGNs
- Short Name:
- J/ApJ/874/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a parsec-scale jet kinematics study of 409 bright radio-loud active galactic nuclei (AGNs) based on 15GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2016 December 26 as part of the 2cm VLBA survey and Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) programs. We tracked 1744 individual bright features in 382 jets over at least 5 epochs. A majority (59%) of the best-sampled jet features showed evidence of accelerated motion at the >3{sigma} level. Although most features within a jet typically have speeds within ~40% of a characteristic median value, we identified 55 features in 42 jets that had unusually slow pattern speeds, nearly all of which lie within 4pc (100pc deprojected) of the core feature. Our results, combined with other speeds from the literature, indicate a strong correlation between apparent jet speed and synchrotron peak frequency, with the highest jet speeds being found only in low-peaked AGNs. Using Monte Carlo simulations, we find best-fit parent population parameters for a complete sample of 174 quasars above 1.5Jy at 15GHz. Acceptable fits are found with a jet population that has a simple unbeamed power-law luminosity function incorporating pure luminosity evolution and a power-law Lorentz factor distribution ranging from 1.25 to 50 with slope -1.4+/-0.2. The parent jets of the brightest radio quasars have a space density of 261+/-19Gpc^-3^ and unbeamed 15GHz luminosities above ~10^24.5^W/Hz, consistent with FRII class radio galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A52
- Title:
- Molecular cloud formation in M33
- Short Name:
- J/A+A/548/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The amount of H_2_ present in spiral galaxies remains uncertain, particularly in the dim outer regions and in low-metallicity environments. We present high-resolution CO(1-0) observations with the Plateau de Bure interferometer of the most distant molecular cloud in the local group galaxy M33. The cloud is a single entity rather than a set of smaller clouds within the broad beam of the original single-dish observations. The interferometer and single-dish fluxes are very similar and the line widths are indistinguishable, despite the difference in beamsize.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/136
- Title:
- Molecular clouds in the Antennae from CO(2-1)
- Short Name:
- J/ApJ/750/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Super star clusters--extremely massive clusters found predominately in starburst environments--are essential building blocks in the formation of galaxies and thought to dominate star formation in the high-redshift universe. However, the transformation from molecular gas into these ultracompact star clusters is not well understood. To study this process, we used the Submillimeter Array and the Plateau de Bure Interferometer to obtain high angular resolution (~1.5" or 160pc) images of the Antennae overlap region in CO(2-1) to search for the molecular progenitors of the super star clusters. We resolve the molecular gas distribution into a large number of clouds, extending the differential cloud mass function down to a 5{sigma} completeness limit of 3.8x10^5^M_{sun}_. We identify a distinct break in the mass function around log M_mol_/M_{sun}_{approx}6.5, which separates the molecular clouds into two distinct populations. The smaller, less massive clouds reside in more quiescent areas in the region, while the larger, more massive clouds cluster around regions of intense star formation. A broken power-law fit to the mass function yields slopes of {alpha}=-1.39+/-0.10 and {alpha}=-1.44+/-0.14 for the low- and high-mass cloud population, well matched to the mass function found for super star clusters in the Antennae galaxies. We find large velocity gradients and velocity dispersions at the locations of intense star formation, suggestive of compressive shocks. It is likely that these environmental factors contribute to the formation of the observed massive molecular clouds and super star clusters in the Antennae galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/278
- Title:
- Molecular clouds in the dwarf galaxy NGC6822
- Short Name:
- J/ApJ/835/278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Atacama Large Millimeter/submillimeter Array survey of CO(2-1) emission from the 1/5 solar metallicity, Local Group dwarf galaxy NGC 6822. We achieve high (0.9"~2pc) spatial resolution while covering a large area: four 250pcx250pc regions that encompass ~2/3 of NGC 6822's star formation. In these regions, we resolve ~150 compact CO clumps that have small radii (~2-3pc), narrow line width (~1km/s), and low filling factor across the galaxy. This is consistent with other recent studies of low-metallicity galaxies, but here shown with a 15x larger sample. At parsec scales, CO emission correlates with 8{mu}m emission better than with 24{mu}m emission and anticorrelates with H{alpha}, so that polycyclic aromatic hydrocarbon emission may be an effective tracer of molecular gas at low metallicity. The properties of the CO clumps resemble those of similar-size structures in Galactic clouds except of slightly lower surface brightness and with CO-to-H_2_ ratio ~1-2x the Galactic value. The clumps exist inside larger atomic-molecular complexes with masses typical for giant molecular clouds. Using dust to trace H_2_ for the entire complex, we find the CO-to-H_2_ ratio to be ~20-25x the Galactic value, but with strong dependence on spatial scale and variations between complexes that may track their evolutionary state. The H_2_-to-HI ratio is low globally and only mildly above unity within the complexes. The ratio of star formation rate to H_2_ is ~3-5x higher in the complexes than in massive disk galaxies, but after accounting for the bias from targeting star-forming regions, we conclude that the global molecular gas depletion time may be as long as in massive disk galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A148
- Title:
- 12 molecular clouds of M31 spectra
- Short Name:
- J/A+A/625/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse molecular observations performed at IRAM interferometer in CO(1-0) of the circum-nuclear region (within 250pc) of Andromeda, with 2. arcsec=11pc resolution. We detect 12 molecular clumps in this region, corresponding to a total molecular mass of (8.4+/ 0.4)x10^4^M_{sun}_. They follow the Larson's mass-size relation, but lie well above the velocity-size relation. We discuss that these clumps are probably not virialised, but transient agglomerations of smaller entities that might be virialised. Three of these clumps have been detected in CO(2-1) in a previous work, and we find temperature line ratio below 0.5. With a RADEX analysis, we show that this gas is in non local thermal equilibrium with a low excitation temperature (Tex=5-9K). We find a surface beam filling factor of order 5 percent and a gas density in the range 60-650cm^-3^, well below the critical density. With a gas-to-stellar mass fraction of 4x10^-4^ and dust-to-gas ratio of 0.01, this quiescent region has exhausted his gas budget. Its spectral energy distribution is compatible with passive templates assembled from elliptical galaxies. While weak dust emission is present in the region, we show that no star formation is present and support the previous results that the dust is heated by the old and intermediate stellar population. We study that this region lies formally in the low-density part of the Kennicutt-Schmidt law, in a regime where the SFR estimators are not completely reliable. We confirm the quiescence of the inner part of this galaxy known to lie on the green valley.
- ID:
- ivo://CDS.VizieR/J/A+A/327/522
- Title:
- Molecular gas content of spiral galaxies
- Short Name:
- J/A+A/327/522
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 12CO(J=1-0) line observations of 73 spiral galaxies mostly in the Coma/A1367 supercluster. From these data, combined with data available in the literature, we extract the first complete, optically selected sample (mpg<15.2) of 37 isolated and of 27 cluster galaxies. The 12CO(1-0) line spectra are accessible as postscript figures.