Search

Start Over Subject submillimeter astronomy Validation Level 2
461. SPT-S J041839-4751.8 APEX spectra
ID:
ivo://CDS.VizieR/J/A+A/631/A167
Title:
SPT-S J041839-4751.8 APEX spectra
Short Name:
J/A+A/631/A167
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of six far-infrared fine structure lines in the z=4.225 lensed dusty star-forming galaxy SPT 0418-47 (SPT-S J041839-4751.8) to probe the physical conditions of its inter stellar medium (ISM). In particular, we report Atacama Pathfinder EXperiment (APEX) detections of the [OI] 145um and [OIII] 88um lines and Atacama Compact Array (ACA) detections of the [NII] 122 and 205um lines. The [OI] 145um/[CII] 158um line ratio is ~5x higher compared to the average of local galaxies. We interpret this as evidence that the ISM is dominated by photo-dissociation regions with high gas densities. The line ratios, and in particular those of [OIII] 88um and [NII] 122um imply that the ISM in SPT 0418-47 is already chemically enriched to nearly solar metallicity. While the strong gravitational amplification was required to detect these lines with APEX, larger samples can be observed with the Atacama Large Millimeter/submillimeter Array (ALMA), and should allow observers to determine if the dense, solar metallicity ISM is common among these highly star-forming galaxies.
462. SPT-SZ survey point sources at 95, 150 & 220GHz
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.
463. Star formation in Ophiuchus and Perseus II.
ID:
ivo://CDS.VizieR/J/ApJ/683/822
Title:
Star formation in Ophiuchus and Perseus II.
Short Name:
J/ApJ/683/822
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a census of the population of deeply embedded young stellar objects (YSOs) in the Ophiuchus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We have applied a method developed for identifying embedded protostars in Perseus to these data sets and in this way construct a relatively unbiased sample of 27 candidate embedded protostars with envelopes more massive than our sensitivity limit (about 0.1M_{sun}_).
464. Stars associated to Eagle Nebula (M16=NGC6611)
ID:
ivo://CDS.VizieR/J/A+A/521/A61
Title:
Stars associated to Eagle Nebula (M16=NGC6611)
Short Name:
J/A+A/521/A61
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive star-forming regions are characterized by intense ionizing fluxes, strong stellar winds and, occasionally, supernovae explosions, all of which have important effects on the surrounding media, on the star-formation process and on the evolution of young stars and their circumstellar disks. We present a multiband study of the massive young cluster NGC 6611 and its parental cloud (the Eagle Nebula) with the aim of studying how OB stars affect the early stellar evolution and the formation of other stars. We search for evidence of triggering of star formation by the massive stars inside NGC 6611 on a large spatial scale (~10 parsec) and ongoing disk photoevaporation in NGC 6611 and how its efficiency depends on the mass of the central stars.
465. Statisical study of galaxy dust emissions
ID:
ivo://CDS.VizieR/J/MNRAS/421/3027
Title:
Statisical study of galaxy dust emissions
Short Name:
J/MNRAS/421/3027
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use the Herschel-ATLAS survey to conduct the first large-scale statistical study of the submillimetre properties of optically selected galaxies. Using ~80000 r-band selected galaxies from 126deg^2^ of the GAMA survey, we stack into submillimetre imaging at 250, 350 and 500um to gain unprecedented statistics on the dust emission from galaxies at z<0.35. We find that low-redshift galaxies account for 5 per cent of the cosmic 250-um background (4 per cent at 350um; 3 per cent at 500um), of which approximately 60 per cent comes from 'blue' and 20 per cent from 'red' galaxies (rest-frame g-r).
466. 12 strong galactic bars CO spectra
ID:
ivo://CDS.VizieR/J/A+A/654/A135
Title:
12 strong galactic bars CO spectra
Short Name:
J/A+A/654/A135
Date:
22 Feb 2022
Publisher:
CDS
Description:
While some galactic bars show recent massive star formation (SF) along them, some others present a lack of it. Whether bars with low level of SF are a consequence of low star formation efficiency, low gas inflow rate, or dynamical effects, remains a matter of debate. In order to study the physical conditions that enable or prevent SF, we perform a multi-wavelength analysis of 12 strongly barred galaxies with total stellar masses log10(M*/M_{sun}_){in}[10.2,11], chosen to host different degrees of SF along the bar major axis without any prior condition on gas content. We observe the CO(1-0) and CO(2-1) emission within bars with the IRAM-30m telescope (beam sizes of 1.7-3.9kpc and 0.9-2.0kpc, respectively; 7-8 pointings per galaxy on average). We estimate molecular gas masses (Mmol) from the CO(1-0) and CO(2-1) emissions. SF rates (SFR) are calculated from GALEX near-ultraviolet (UV) and WISE 12um images within the beam-pointings, covering the full bar extent (SFRs are also derived from far-UV and 22um). Results. We detect molecular gas along the bars of all probed galaxies. Molecular gas and SFR surface densities span the ranges log10({Sigma}_mol_/[M_{sun}_/pc^2^]){in}[0.4,2.4] and log10({Sigma}_SFR_/[M_{sun}_/pc/kpc^2^]){in}[-3.25,-0.75], respectively. The star formation efficiency (SFE=SFR/Mmol) in bars varies between galaxies by up to an order of magnitude (SFE{in}[0.1,1.8]Gyr^-1^). On average, SFEs are roughly constant along bars. SFEs are not significantly different from the mean value in spiral galaxies reported in the literature (~0.43Gyr^-1^), regardless of whether we estimate Mmol from CO(1-0) or CO(2-1). Interestingly, the higher the total stellar mass of the host galaxy, the lower the SFE within their bars. In particular, the two galaxies in our sample with lowest SFE and {Sigma}_SFR_ (NGC 4548 and NGC 5850, SFE<=0.25Gyr^-1^, {Sigma}_SFR_<=10^-2.25^M_{sun}_/yr/kpc^2^, M*<=10^10.7^M_{sun}_) are also the ones hosting massive bulges and signs of past interactions with nearby companions. We present a statistical analysis of the SFE in bars for a sample of 12 galaxies. The SFE in strong bars is not systematically inhibited (either in the central, mid- or end-parts of the bar). Both environmental and internal quenching are likely responsible for the lowest SFEs reported in this work.
467. Strongly lensed submm galaxies CO spectra
ID:
ivo://CDS.VizieR/J/A+A/608/A144
Title:
Strongly lensed submm galaxies CO spectra
Short Name:
J/A+A/608/A144
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the IRAM-30m observations of multiple-J CO (J_up_ mostly from 3 up to 8) and [CI](^3^P_2_ -> ^3^P_1_) ([CI](2-1) hereafter) line emission in a sample of redshift ~2-4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). 47 CO lines and 7 [CI](2-1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around J_up_~5-7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density n_H2_~10^2.5^-10^4.1^cm^-3^ and the kinetic temperature T_k_~20-750K. The gas thermal pressure P_{th} ranging from ~10^5^K/cm^3^ to 10^6^K/cm^3^ is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with n_H2_~10^2.8^-10^4.6^cm^-3^ and T_k_~20-30K, which is less correlated with star formation, and a high-excitation one (n_H2_~10^2.7^-10^4.2^cm^-3^, T_k_~60-400K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the J_up_>=5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [CI](2-1) lines follow the tight linear correlation between the luminosities of the [CI](2-1) and the CO(1-0) line found in local starbursts, indicating that [CI] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well. The total mass of the molecular gas reservoir, (1-30)x10^10^M_{sun}_, derived based on the CO(3-2) fluxes and {alpha}_CO(1-0)_=0.8M_{sun}_/(K.km/s/pc^2), suggests a typical molecular gas depletion time t_dep_~20-100Myr and a gas to dust mass ratio {delta}_GDR_~30-100 with ~20%-60% uncertainty for the SMGs. The ratio between CO line luminosity and the dust mass L'_CO(1-0)_/M_{dust} appears to be slowly increasing with redshift for high-redshift SMGs, which CO need to be further confirmed by a more complete SMG sample at various redshifts. Finally, through comparing the linewidth of CO and H_2_O lines, we find that they agree well in almost all our SMGs, confirming that the emitting regions of the CO and H_2_O lines are co-spatially located.
468. Structures of dust in Perseus molecular cloud
ID:
ivo://CDS.VizieR/J/ApJ/646/1009
Title:
Structures of dust in Perseus molecular cloud
Short Name:
J/ApJ/646/1009
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of 3.5deg^2^ of submillimeter continuum and extinction data of the Perseus molecular cloud. We identify 58 clumps in the submillimeter map, and we identify 39 structures (cores) and 11 associations of structures (super cores) in the extinction map. The cumulative mass distributions of the submillimeter clumps and extinction cores have steep slopes (alpha~2 and 1.5-2, respectively), steeper than the Salpeter initial mass function (IMF; alpha=1.35), while the distribution of extinction super cores has a shallow slope (alpha~1). Most of the submillimeter clumps are well fit by stable Bonnor-Ebert spheres with 10K<T<19K and 5.5<log_10_(Pext/k)<0.6. The clumps are found only in the highest column density regions (AV>5-7mag), although Bonnor-Ebert models suggest that we should have been able to detect them at lower column densities if they exist.
469. STUDIES. III. SCUBA-2 450um gal. with MIPS & VLA obs.
ID:
ivo://CDS.VizieR/J/ApJ/889/80
Title:
STUDIES. III. SCUBA-2 450um gal. with MIPS & VLA obs.
Short Name:
J/ApJ/889/80
Date:
11 Mar 2022
Publisher:
CDS
Description:
We construct a SCUBA-2 450{mu}m map in the COSMOS field that covers an area of 300arcmin^2^ and reaches a 1{sigma} noise level of 0.65mJy in the deepest region. We extract 256 sources detected at 450{mu}m with signal-to-noise ratios >4.0 and analyze the physical properties of their multiwavelength counterparts. We find that most of the sources are at z<~3, with a median of z=1.79_-0.15_^+0.03^%. About 35_-25_^+32^% of our sources are classified as starburst galaxies based on their total star formation rates (SFRs) and stellar masses (M_*_). By fitting the far-infrared spectral energy distributions, we find that our 450{mu}m selected sample has a wide range of dust temperatures (20K<~T_d_<~60K), with a median of T_d_=38.3_-0.9_^+0.4^K. We do not find a redshift evolution in dust temperature for sources with L_IR_>10^12^L_{sun}_ at z<3. However, we find a moderate correlation where the dust temperature increases with the deviation from the SFR-M_*_ relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in submillimeter galaxies. Our galaxies do not show the tight IRX-{beta}_UV_ correlation that has been observed in the local universe. We construct the infrared luminosity functions of our 450{mu}m sources and measure their comoving SFR densities (SFRDs). The contribution of the L_IR_>10^12^L_{sun}_ population to the SFRD rises dramatically from z=0 to 2 ({propto}(1+z)^3.9+/-1.1^) and dominates the total SFRD at z>~2.
470. STUDIES. II. NIR morphologies of submm galaxies
ID:
ivo://CDS.VizieR/J/ApJ/865/103
Title:
STUDIES. II. NIR morphologies of submm galaxies
Short Name:
J/ApJ/865/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present structural parameters and morphological properties of faint 450{mu}m selected submillimeter galaxies (SMGs) from the JCMT Large Program, STUDIES, in the COSMOS-CANDELS region. Their properties are compared to an 850{mu}m selected and a matched star-forming samples. We investigate stellar structures of 169 faint 450{mu}m sources (S_450_=2.8-29.6mJy; S/N>4) at z<3 using HST near-infrared observations. Based on our spectral energy distribution fitting, half of such faint SMGs (L_IR_=10^11.65^+/-0.98^L_{sun}_) lie above the star formation rate (SFR)/stellar mass plane. The size-mass relation shows that these SMGs are generally similar to less-luminous star-forming galaxies selected by NUV-r versus r-J colors. Because of the intrinsic luminosity of the sample, their rest-frame optical emission is less extended than the 850{mu}m sources (S_850_>2mJy) and more extended than the star-forming galaxies in the same redshift range. For the stellar mass and SFR-matched sample at z~1 and z~2, the size differences are marginal between faint SMGs and the matched galaxies. Moreover, faint SMGs have similar Sersic indices and projected axis ratios as star-forming galaxies with the same stellar mass and SFR. Both SMGs and the matched galaxies show high fractions (~70%) of disturbed features at z~2, and the fractions depend on the SFRs. These suggest that their star formation activity is related to galaxy merging and the stellar structures of SMGs are similar to those of star-forming galaxies. We show that the depths of submillimeter surveys are approaching the lower luminosity end of star-forming galaxies, allowing us to detect galaxies on the main sequence.