- ID:
- ivo://CDS.VizieR/J/ApJS/206/9
- Title:
- New EGOs from Spitzer GLIMPSE II survey. I.
- Short Name:
- J/ApJS/206/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have produced a catalog containing 98 newly identified massive young stellar object (MYSO) candidates associated with ongoing outflows (known as extended green objects, or EGOs). These have been identified from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) II data set and our new identifications increase the number of known EGOs to ~400 in our Galaxy, adding to the ~300 previously identified EGOs reported by Cyganowski et al. (2008, Cat. J/AJ/136/2391) from the GLIMPSE I survey. The high detection rate (~70%) of 95 GHz class I methanol masers achieved in a survey toward 57 of these new EGOs with the Mopra 22m radio telescope demonstrates that the new EGOs are associated with outflows. Investigations of the mid-infrared properties and physical associations with other star formation tracers (e.g., infrared dark clouds, class I and II methanol masers, and millimeter Bolocam Galactic Plane Survey sources) reveal that the newly identified EGOs are very similar in nature to those in the sample of Cyganowski et al. All of the observational evidence supports the hypothesis that EGOs correspond to MYSOs at the earliest evolutionary stage, with ongoing outflow activity, and active rapid accretion.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/206/22
- Title:
- Newly EGOs from GLIMPSE II survey. II. MoC
- Short Name:
- J/ApJS/206/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have undertaken a survey of molecular lines in the 3mm band toward 57 young stellar objects using the Australia Telescope National Facility Mopra 22m radio telescope. The target sources were young stellar objects with active outflows (extended green objects (EGOs)) newly identified from the GLIMPSE II survey. We observe a high detection rate (50%) of broad line wing emission in the HNC and CS thermal lines, which combined with the high detection rate of class I methanol masers toward these sources (reported in Paper I, Cat. J/ApJS/206/9) further demonstrates that the GLIMPSE II EGOs are associated with outflows. The physical and kinematic characteristics derived from the 3mm molecular lines for these newly identified EGOs are consistent with these sources being massive young stellar objects with ongoing outflow activity and rapid accretion. These findings support our previous investigations of the mid-infrared properties of these sources and their association with other star formation tracers (e.g., infrared dark clouds, methanol masers and millimeter dust sources) presented in Paper I. The high detection rate (64%) of the hot core tracer CH_3_CN reveals that the majority of these new EGOs have evolved to the hot molecular core stage. Comparison of the observed molecular column densities with predictions from hot core chemistry models reveals that the newly identified EGOs from the GLIMPSE II survey are members of the youngest hot core population, with an evolutionary time scale of the order of 10^3^yr.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/27
- Title:
- New point sources in the WMAP 7yr data
- Short Name:
- J/ApJ/753/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a new needlet-based method to detect point sources in cosmic microwave background (CMB) maps and have applied it to the Wilkinson Microwave Anisotropy Probe (WMAP) 7 year data. We use both the individual frequency channels as well as internal templates, the latter being the difference between pairs of frequency channels and hence having the advantage that the CMB component is eliminated. Using the area of the sky outside the Kq85 galactic mask, we detect a total of 2102 point sources at the 5{sigma} level in either the frequency maps or the internal templates. Of these, 1116 are detected either at 5{sigma} directly in the frequency channels or at 5{sigma} in the internal templates and >=3{sigma} at the corresponding position in the frequency channels. Of the 1116 sources, 603 are detections that have not been reported so far in WMAP data. We have made a catalog of these sources available with position and flux estimated in the WMAP channels where they are seen. In total, we identified 1029 of the 1116 sources with counterparts at 5GHz and 69 at other frequencies.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A33
- Title:
- NGC 613 ALMA datacubes
- Short Name:
- J/A+A/632/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report ALMA observations of CO(3-2) emission in the Seyfert/nuclear starburst galaxy NGC613, at a spatial resolution of 17pc, as part of our NUclei of GAlaxies (NUGA) sample. Our aim is to investigate the morphology and dynamics of the gas inside the central kiloparsec, and to probe nuclear fueling and feedback phenomena. The morphology of CO(3-2) line emission reveals a two arm trailing nuclear spiral at r<~100pc and a circumnuclear ring at a radius of ~350pc that is coincident with the star-forming ring seen in the optical images. Also, we find evidence for a filamentary structure connecting the ring and the nuclear spiral. The ring reveals two breaks into two winding spiral arms corresponding to the dust lanes in the optical images. The molecular gas in the galaxy disk is in a remarkably regular rotation, however the kinematics in the nuclear region are very skewed. The nuclear spectrum of CO and dense gas tracers HCN(4-3), HCO^+^(4-3), and CS(7-6) show broad wings up to 300km/s, associated with a molecular outflow emanating from the nucleus (r~25pc). We derive a molecular outflow mass M_out_=2x10^6^M_[sun}_ and a mass outflow rate of dM_out_/dt=27M_[sun}/yr. The molecular outflow energetics exceed the values predicted by AGN feedback models: the kinetic power of the outflow corresponds to P_K,out_=20%L_AGN_ and the momentum rate is dM_out_/dt*v~400L_AGN_/c. The outflow is mainly boosted by the AGN through entrainment by the radio jet, but given the weak nuclear activity of NGC613, we might be witnessing a fossil outflow resulting from a previously strong AGN that has now faded. Furthermore, the nuclear trailing spiral observed in CO emission is inside the inner Lindblad resonance ring of the bar. We compute the gravitational torques exerted in the gas to estimate the efficiency of the angular momentum exchange. The gravity torques are negative from 25 to 100pc and the gas loses its angular momentum in a rotation period, providing evidence for a highly efficient inflow towards the center. This phenomenon shows that the massive central black hole has significant dynamical influence on the gas, triggering the inflowing of molecular gas to feed the black hole.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A2
- Title:
- NGC6334 ALMA 87.6GHz continuum emission map
- Short Name:
- J/A+A/635/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to characterise certain physical properties of high-mass star-forming sites in the NGC6334 molecular cloud, such as the core mass function (CMF), spatial distribution of cores, and mass segregation. We used the Atacama Large Millimetre/sub-millimetre Array (ALMA) to image the embedded clusters NGC6334-I and NGC6334-I(N) in the continuum emission at 87.6GHz. We achieved a spatial resolution of 1300au, enough to resolve different compact cores and fragments, and to study the properties of the clusters. We detected 142 compact sources distributed over the whole surveyed area. The ALMA compact sources are clustered in different regions. We used different machine-learning algorithms to identify four main clusters: NGC6334-I, NGC6334-I(N), NGC6334-I(NW), and NGC6334-E. The typical separations between cluster members range from 4000au to 12000au. These separations, together with the core masses (0.1-100M_{sun}_), are in agreement with the fragmentation being controlled by turbulence at scales of 0.1pc. We find that the CMFs show an apparent excess of high-mass cores compared to the stellar Initial Mass Function. We evaluated the effects of temperature and unresolved multiplicity on the derived slope of the CMF. Based on this, we conclude that the excess of high-mass cores might be spurious and due to inaccurate temperature determinations and/or resolution limitations. We searched for evidence of mass segregation in the clusters and we find that clusters NGC6334-I and NGC6334-I(N) show hints of segregation with the most massive cores located in the centre of the clusters. We searched for correlations between the physical properties of the four embedded clusters and their evolutionary stage (based on the presence of Hii regions and infrared sources). NGC6334-E appears as the most evolved cluster, already harboring a well-developed Hii region. NGC6334-I is the second-most evolved cluster with an ultra-compact Hii region. NGC6334-I(N) contains the largest population of dust cores distributed in two filamentary structures and no dominant Hii region. Finally, NGC6334-I(NW) is a cluster of mainly low-mass dust cores with no clear signs of massive cores or Hii regions.We find a larger separation between cluster members in the more evolved clusters favoring the role of gas expulsion and stellar ejection with evolution. The mass segregation, seen in the NGC6334-I and NGC6334-I(N) clusters, suggests a primordial origin for NGC6334-I(N). In contrast, the segregation in NGC6334-I might be due to dynamical effects. Finally, the lack of massive cores in the most evolved cluster suggests that the gas reservoir is already exhausted, while the less evolved clusters still have a large gas reservoir along with the presence of massive cores. In general, the fragmentation process of NGC6334 at large scales (from filament to clump, i.e. at about 1pc) is likely governed by turbulent pressure, while at smaller scales (scale of cores and sub-fragments, i.e. a few hundred au) thermal pressure starts to be more significant.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A91
- Title:
- NGC 4418 ALMA mm-wave spectral scan
- Short Name:
- J/A+A/582/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic observations allow the study of molecular chemistry and excitation under physical conditions which may differ greatly from what found in the Milky Way. The compact, obscured nuclei (CON) of luminous infrared galaxies (LIRG) combine large molecular columns with intense infrared (IR), ultra-violet (UV) and X- radiation and represent ideal laboratories to study the chemistry of the interstellar medium (ISM) under extreme conditions. To obtain for the first time a multi-band spectral scan of a LIRG, in order to derive the molecular abundances and excitation, to be compared to other Galactic and extragalactic environments. We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total of 70.7GHz in bands 3, 6, and 7. We use a combined local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum in order to identify the molecular species and derive column densities and excitation temperatures. We derive molecular abundances and compare them with other Galactic and extragalactic sources by means of a principal component analysis.
- ID:
- ivo://CDS.VizieR/J/A+A/599/A9
- Title:
- NGC 4214 [CII] line profile
- Short Name:
- J/A+A/599/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used SOFIA/GREAT [CII] 158um observations as well as HI data from THINGS and CO(2-1) data from HERACLES to decompose the spectrally resolved [CII] line profiles in NGC4124 into components associated with neutral atomic and molecular gas. We infer gas masses traced by [CII] under different ISM conditions. We find that the molecular gas mass is dominated by CO-dark gas and that we can only assign 9 percent of [CII] intensity to the cold neutral medium.
608. NGC 3269 CO spectra
- ID:
- ivo://CDS.VizieR/J/A+A/645/A36
- Title:
- NGC 3269 CO spectra
- Short Name:
- J/A+A/645/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An intriguing silhouette of a small dust patch can be seen against the disk of the S0 galaxy NGC 3269 in the Antlia cluster in optical images. The images do not provide any clue as to whether the patch is a local Jupiter mass-scale cloudlet or a large extragalactic dust complex. We aim to resolve the nature of this object: is it a small Galactic cloudlet or an extragalactic dust complex? ALMA and APEX spectroscopy and Gemini GMOS long-slit spectroscopy were used to measure the velocity of the patch and the NGC 3269 disk radial velocity curve. A weak 16+/-2.5km/s wide ^12^CO (2-1) T_MB_ 19+/-2.5mK line in a 2.2" by 2.12" beam associated with the object was detected with ALMA. The observed heliocentric velocity, V_r,hel_=3878+/-5.0km/s, immediately establishes the extragalactic nature of the object. The patch velocity is consistent with the velocity of the nucleus of NGC 3269, but not with the radial velocity of the NGC 3269 disk of the galaxy at its position. The ~4" angular size of the patch corresponds to a linear size of ~1kpc at the galaxy's Hubble distance of 50.7Mpc. The mass estimated from the ^12^CO (2-1) emission is ~1.4x10^6^(d/50.7Mpc)^2^M_{sun}_, while the attenuation derived from the optical spectrum implies a dust mass of ~2.6x10^4^(d/50.7Mpc)^2^M_{sun}_. The derived attenuation ratio A'_B_/(A'_B_-A'_R_) of 1.6+/-0.11 is substantially lower than the corresponding value for the mean Milky Way extinction curve for point sources (2.3). We established the extragalactic nature of the patch, but its origin remains elusive. One possibility is that the dust patch is left over from the removal of interstellar matter in NGC 3269 through the interaction with its neighbour, NGC 3268.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A83
- Title:
- NGC 6334 filament with ALMA
- Short Name:
- J/A+A/632/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Herschel imaging surveys of galactic interstellar clouds support a paradigm for low-mass star formation in which dense molecular filaments play a crucial role. The detailed fragmentation properties of star-forming filaments remain poorly understood, however, and the validity of the filament paradigm in the intermediate- to high-mass regime is still unclear. Here, following up on an earlier 350um dust continuum study with the ArTeMiS camera on the APEX telescope, we investigate the detailed density and velocity structure of the main filament in the high-mass star-forming region NGC 6334. We conducted ALMA Band 3 observations in the 3.1mm continuum and of the N_2_H^+^(1-0), HC_5_N(36-35), HNC(1-0), HC_3_N(10-9), CH_3_CCH(6-5), and H_2_CS(3-2) lines at an angular resolution of 300, corresponding to 0.025 pc at a distance of 1.7kpc. The NGC 6334 filament was detected in both the 3.1mm continuum and the N_2_H^+^, HC_3_N, HC_5_N, CH_3_CCH, and H_2_CS lines with ALMA. We identified twenty-six compact (<0.03pc) dense cores at 3.1mm and five velocity-coherent fiber-like features in N_2_H^+^ within the main filament. The typical length (~0.5pc) of, and velocity difference (~0.8km/s) between, the fiber-like features of the NGC 6334 filament are reminiscent of the properties for the fibers of the low-mass star-forming filament B211/B213 in the Taurus cloud. Only two or three of the five velocity-coherent features are well aligned with the NGC 6334 filament and may represent genuine, fiber sub-structures; the other two features may trace accretion flows onto the main filament. The mass distribution of the ALMA 3.1mm continuum cores has a peak at 10 M, which is an order of magnitude higher than the peak of the prestellar core mass function in nearby, low-mass star-forming clouds. The cores can be divided into seven groups, closely associated with dense clumps seen in the ArTeMiS 350um data. The projected separation between ALMA dense cores (0.03-0.1pc) and the projected spacing between ArTeMiS clumps (0.2-0.3pc) are roughly consistent with the effective Jeans length (0.08+/-0.03pc) in the filament and a physical scale of about four times the filament width, respectively, if the inclination angle of the filament to line of sight is ~30{deg}. These two distinct separation scales are suggestive of a bimodal fragmentation process in the filament. Despite being one order of magnitude denser and more massive than the Taurus B211/B213 filament, the NGC 6334 filament has a density and velocity structure that is qualitatively very similar. The main difference is that the dense cores embedded in the NGC 6334 filament appear to be an order of magnitude denser and more massive than the cores in the Taurus filament. This suggests that dense molecular filaments may evolve and fragment in a similar manner in low- and high-mass star-forming regions, and that the filament paradigm may hold in the intermediate-mass (if not high-mass) star formation regime.
- ID:
- ivo://CDS.VizieR/J/A+A/637/A63
- Title:
- NGC 1333-IRAS4A radio images
- Short Name:
- J/A+A/637/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-mass protostars drive powerful molecular outflows that can be observed with millimetre and submillimetre telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. The evolution of sulfur chemistry is studied along the outflows driven by the NGC1333-IRAS4A protobinary system located in the Perseus cloud to constrain the physical and chemical processes at work in shocks. We observed various transitions from OCS, CS, SO, and SO_2_ towards NGC1333-IRAS4A in the 1.3, 2, and 3mm bands using the {IRAM NOrthern Extended Millimeter Array (NOEMA)} and we interpreted the observations through the use of the Paris-Durham shock model. The targeted species clearly show different spatial emission along the two outflows driven by IRAS4A. OCS is brighter on small and large scales along the south outflow driven by IRAS4A1, whereas SO_2_ is detected rather along the outflow driven by IRAS4A2 that is extended along the north east - south west (NE-SW) direction. SO is detected at extremely high radial velocity up to +25km/s relative to the source velocity, clearly allowing us to distinguish the two outflows on small scales. Column density ratio maps estimated from a rotational diagram analysis allowed us to confirm a clear gradient of the OCS/SO_2_ column density ratio between the IRAS4A1 and IRAS4A2 outflows. Analysis assuming non Local Thermodynamic Equilibrium of four SO$_2$ transitions towards several SiO emission peaks suggests that the observed gas should be associated with densities higher than 10^5^cm^-3^ and relatively warm (T>100K) temperatures in most cases. The observed chemical differentiation between the two outflows of the IRAS4A system could be explained by a different chemical history. The outflow driven by IRAS4A1 is likely younger and more enriched in species initially formed in interstellar ices, such as OCS, and recently sputtered into the shock gas. In contrast, the longer and likely older outflow triggered by IRAS4A2 is more enriched in species that have a gas phase origin, such as SO_2_.
