- ID:
- ivo://CDS.VizieR/J/A+A/569/A125
- Title:
- Spiral structure of the Milky Way
- Short Name:
- J/A+A/569/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have updated the catalogs of Galactic HII regions, giant molecular clouds (GMCs), and 6.7-GHz methanol masers to outline the spiral structure of our Galaxy. The related parameters have been collected and (re)calculated based on the data in the literature. In particular, for each spiral tracer, we list the photometric or trigonometric distance, and/or the solutions of the kinematic distance ambiguity (KDA) when available. The kinematic distances when adopted are calculated using a flat rotation curve with two sets of R_0_, {Theta}_0_, and solar motions, where one set is the IAU standard and the other is from the new observational results. The rotation curve of Brand & Blitz (1993, Cat. J/A+A/275/67) is also used to derive the kinematic distances.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/660/167
- Title:
- Spitzer AGN candidates in CDFN
- Short Name:
- J/ApJ/660/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We define a sample of 62 galaxies in the Chandra Deep Field-North whose Spitzer IRAC SEDs exhibit the characteristic power-law emission expected of luminous AGNs. We study the multi-wavelength properties of this sample and compare the AGNs selected in this way to those selected via other Spitzer color-color criteria. Only 55% of the power-law galaxies are detected in the X-ray catalog at exposures of >0.5Ms, although a search for faint emission results in the detection of 85% of the power-law galaxies at the >=2.5sigma detection level. Most of the remaining galaxies are likely to host AGNs that are heavily obscured in the X-ray. Because the power-law selection requires the AGNs to be energetically dominant in the near- and mid-infrared, the power-law galaxies comprise a significant fraction of the Spitzer-detected AGN population at high luminosities and redshifts. The high 24um detection fraction also points to a luminous population. The power-law galaxies comprise a subset of color-selected AGN candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/1610
- Title:
- Spitzer survey of submillimeter galaxies
- Short Name:
- J/ApJ/699/1610
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer-IRAC and MIPS mid-IR observations of a sample of 76 radio-detected submillimeter-selected galaxies (SMGs) with spectroscopic redshifts, the largest such sample published to date. From our data, we find that IRAC colors of SMGs are much more uniform as compared with rest-frame UV and optical colors, and z>1.5 SMGs tend to be redder in their mid-IR colors than both field galaxies and lower-z SMGs. However, the IRAC colors of the SMGs overlap those of field galaxies sufficiently that color-magnitude and color-color selection criteria suggested in the literature to identify SMG counterparts produce ambiguous counterparts within an 8" radius in 20%-35% of cases. We use a rest-frame J-H versus H-K color-color diagram and a S24/S8.0 versus S8.0/S4.5 color-color diagram to determine that 13%-19% of our sample are likely to contain active galactic nuclei which dominate their mid-IR emission.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/36
- Title:
- SPLASH-SXDF multi-wavelength photometric catalog
- Short Name:
- J/ApJS/235/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength catalog in the Subaru/XMM-Newton Deep Field (SXDF) as part of the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH). We include the newly acquired optical data from the Hyper-Suprime-Cam Subaru Strategic Program, accompanied by IRAC coverage from the SPLASH survey. All available optical and near-infrared data is homogenized and resampled on a common astrometric reference frame. Source detection is done using a multi-wavelength detection image including the u-band to recover the bluest objects. We measure multi-wavelength photometry and compute photometric redshifts as well as physical properties for ~1.17 million objects over ~4.2deg^2^, with ~800000 objects in the 2.4deg^2^ HSC-Ultra-Deep coverage. Using the available spectroscopic redshifts from various surveys over the range of 0<z<6, we verify the performance of the photometric redshifts and we find a normalized median absolute deviation of 0.023 and outlier fraction of 3.2%. The SPLASH-SXDF catalog is a valuable, publicly available resource, perfectly suited for studying galaxies in the early universe and tracing their evolution through cosmic time.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/61
- Title:
- SPT-SZ survey point sources at 95, 150 & 220GHz
- Short Name:
- J/ApJ/779/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a point-source catalog from 771deg^2^ of the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey at 95, 150, and 220GHz. We detect 1545 sources above 4.5{sigma} significance in at least one band. Based on their relative brightness between survey bands, we classify the sources into two populations, one dominated by synchrotron emission from active galactic nuclei, and one dominated by thermal emission from dust-enshrouded star-forming galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all sources against external catalogs and find 189 unidentified synchrotron sources and 189 unidentified dusty sources. The dusty sources without counterparts are good candidates for high-redshift, strongly lensed submillimeter galaxies. We derive number counts for each population from 1Jy down to roughly 11, 4, and 11mJy at 95, 150, and 220GHz. We compare these counts with galaxy population models and find that none of the models we consider for either population provide a good fit to the measured counts in all three bands. The disparities imply that these measurements will be an important input to the next generation of millimeter-wave extragalactic source population models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/500/3821
- Title:
- Square Kilometre Array Science Data Challenge 1
- Short Name:
- J/MNRAS/500/3821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As the largest radio telescope in the world, the Square Kilometre Array (SKA) will lead the next generation of radio astronomy. The feats of engineering required to construct the telescope array will be matched only by the techniques developed to exploit the rich scientific value of the data. To drive forward the development of efficient and accurate analysis methods, we are designing a series of data challenges that will provide the scientific community with high-quality datasets for testing and evaluating new techniques. In this paper we present a description and results from the first such Science Data Challenge (SDC1). Based on SKA MID continuum simulated observations and covering three frequencies (560MHz, 1400MHz and 9200MHz) at three depths (8h, 100h and 1000h), SDC1 asked participants to apply source detection, characterization and classification methods to simulated data. The challenge opened in November 2018, with nine teams submitting results by the deadline of April 2019. In this work we analyse the results for 8 of those teams, showcasing the variety of approaches that can be successfully used to find, characterise and classify sources in a deep, crowded field. The results also demonstrate the importance of building domain knowledge and expertise on this kind of analysis to obtain the best performance. As high-resolution observations begin revealing the true complexity of the sky, one of the outstanding challenges emerging from this analysis is the ability to deal with highly resolved and complex sources as effectively as the unresolved source population.
- ID:
- ivo://CDS.VizieR/J/MNRAS/467/L31
- Title:
- SS Cyg rapid radio flaring in 2016
- Short Name:
- J/MNRAS/467/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The connection between accretion and jet production in accreting white dwarf binary systems, especially dwarf novae, is not well understood. Radio wavelengths provide key insights into the mechanisms responsible for accelerating electrons, including jets and outflows. Here, we present densely sampled radio coverage, obtained with the Arcminute MicroKelvin Imager Large Array, of the dwarf nova SS Cyg during its 2016 February anomalous outburst. The outburst displayed a slower rise (3d/mag) in the optical than typical ones and lasted for more than three weeks. Rapid radio flaring on time-scales <1h was seen throughout the outburst. The most intriguing behaviour in the radio was towards the end of the outburst where a fast, luminous ('giant'), flare peaking at ~20mJy and lasting for 15min was observed. This is the first time that such a flare has been observed in SS Cyg and insufficient coverage could explain its non-detection in previous outbursts. These data, together with past radio observations, are consistent with synchrotron emission from plasma ejection events as being the origin of the radio flares. However, the production of the giant flare during the declining accretion rate phase remains unexplained within the standard accretion-jet framework and appears to be markedly different to similar patterns of behaviour in X-ray binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A6
- Title:
- 3 starburst galaxies 12C/13C ALMA datacubes
- Short Name:
- J/A+A/629/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive molecular-gas-phase ^12^C/^13^C isotope ratios for the central few hundred parsecs of the three nearby starburst galaxies NGC253, NGC1068, and NGC4945 making use of the {lambda}~3mm ^12^CN and ^13^CN N=1-0 lines in the ALMA Band 3. The ^12^C/^13^C isotopic ratios derived from the ratios of these lines range from 30 to 67 with an average of 41.6+/-0.2 in NGC253, from 24 to 62 with an average of 38.3+/-0.4 in NGC1068, and from 6 to 44 with an average of 16.9+/-0.3 in NGC4945. The highest ^12^C/^13^C isotopic ratios are determined in some of the outskirts of the nuclear regions of the three starburst galaxies. The lowest ratios are associated with the northeastern and southwestern molecular peaks of NGC253, the northeastern and southwestern edge of the mapped region in NGC1068, and the very center of NGC4945. In the case of NGC 1068, the measured ratios suggest inflow from the outer part of NGC1068 into the circum-nuclear disk through both the halo and the bar. Low ^12^C/^13^C isotopic ratios in the central regions of these starburst galaxies indicate the presence of highly processed material.
- ID:
- ivo://CDS.VizieR/J/ApJ/733/87
- Title:
- Star formation efficiency in galaxies
- Short Name:
- J/ApJ/733/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose an "extended Schmidt law" with explicit dependence of the star formation efficiency (SFE=SFR/M_gas_) on the stellar mass surface density ({Sigma}_star_). This relation has a power-law index of 0.48+/-0.04 and a 1{sigma} observed scatter on the SFE of 0.4 dex, which holds over five orders of magnitude in the stellar density for individual global galaxies, including various types and especially the low-surface-brightness (LSB) galaxies that deviate significantly from the Kennicutt-Schmidt (KS) law. When applying it to regions of a sample of 12 spiral galaxies at sub-kiloparsec resolution, the extended Schmidt law not only holds for LSB regions but also shows significantly smaller scatters both within and across galaxies compared with the KS law. We argue that this new relation points to the role of existing stars in regulating the SFE, thus better encoding the star formation physics. Comparison with physical models of star formation recipes shows that the extended Schmidt law can be reproduced by some models including gas free fall in a stellar-gravitational potential and pressure-supported star formation. By implementing this new law into the analytic model of gas accretion in {Lambda}CDM, we show that it can reproduce the observed main sequence of star-forming galaxies (a relation between the SFR and stellar mass) from z=0 up to z=2.
- ID:
- ivo://CDS.VizieR/J/AJ/136/2782
- Title:
- Star formation efficiency in nearby galaxies
- Short Name:
- J/AJ/136/2782
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the star formation efficiency (SFE), the star formation rate (SFR) per unit of gas, in 23 nearby galaxies and compare it with expectations from proposed star formation laws and thresholds. We use HI maps from The HI Nearby Galaxy Survey (THINGS) and derive H_2_ maps of CO measured by HERA CO-Line Extragalactic Survey and Berkeley-Illinois-Maryland Association Survey of Nearby Galaxies. We estimate the SFR by combining Galaxy Evolution Explorer (GALEX) far-ultraviolet maps and the Spitzer Infrared Nearby Galaxies Survey (SINGS) 24um maps, infer stellar surface density profiles from SINGS 3.6um data, and use kinematics from THINGS.
