Submillimeter Polarization Spectrum of the Carina Nebula
Jamil A. Shariff, Peter A. R. Ade, Francesco E. Angilè, Peter Ashton, Steven J. Benton, Mark J. Devlin, Bradley Dober, Laura M. Fissel, Yasuo Fukui, Nicholas Ga… 展开作者
Jamil A. Shariff, Peter A. R. Ade, Francesco E. Angilè, Peter Ashton, Steven J. Benton, Mark J. Devlin, Bradley Dober, Laura M. Fissel, Yasuo Fukui, Nicholas Galitzki, Natalie N. Gandilo, Jeffrey Klein, Andrei L. Korotkov, Zhi-Yun Li, Peter G. Martin, Tristan G. Matthews, Lorenzo Moncelsi, Fumitaka Nakamura, Calvin B. Netterfield, Giles Novak, Enzo Pascale, Frédérick Poidevin, Fabio P. Santos, Giorgio Savini, Douglas Scott, Juan D. Soler, Nicholas E. Thomas, Carole E. Tucker, Gregory S. Tucker, Derek Ward-Thompson
Linear polarization maps of the Carina Nebula were obtained at 250, 350, and 500 $μ$m during the 2012 flight of the BLASTPol balloon-borne telescope. These measurements are combined with Planck 850 $μ$m data in order to produce a submillimeter spectrum of the polarization fraction of the dust emission, averaged over the cloud. This spectrum is flat to within $\pm$15% (relative to the 350 $μ$m polarization fraction). In particular, there is no evidence for a pronounced minimum of the spectrum near 350 $μ$m, as suggested by previous ground-based measurements of other molecular clouds. This result of a flat polarization spectrum in Carina is consistent with recently-published BLASTPol measurements of the Vela C molecular cloud, and also agrees with a published model for an externally-illuminated, dense molecular cloud by Bethell and collaborators. The shape of the spectrum in Carina does not show any dependence on the radiative environment of the dust, as quantified by the Planck-derived dust temperature or dust optical depth at 353 GHz.
The Carina Nebula is one of the youngest, most active sites of massive star formation in our Galaxy. In this nebula, we have discovered a bright X-ray source that has persisted for ~30 years. The soft X-ray spectrum, consistent with kT ~128 eV blackbody radiation with mild extinction, and no counterpart in the near- and mid-infrared wavelengths indicate that it is a ~1e6-year-old neutron star housed in the Carina Nebula. Current star formation theory does not suggest that the progenitor of the neutron star and massive stars in the Carina Nebula, in particular Eta Carinae, are coeval. This resu…
The new results of our observing campaign targeting the isolated neutron star 2XMM J104608.7-594306 in the Carina Nebula are used to understand how peculiar groups of isolated neutron stars relate to each other, as well as to the bulk of the normal radio pulsar population.
Herein, we present results from observations of the 12CO (J=1-0), 13CO (J=1-0), and 12CO (J=2-1) emission lines toward the Carina nebula complex (CNC) obtained with the Mopra and NANTEN2 telescopes. We focused on massive-star-forming regions associated with the CNC including the three star clusters Tr14, Tr15, and Tr16, and the isolated WR-star HD92740. We found that the molecular clouds in the CNC are separated into mainly four clouds at velocities -27, -20, -14, and -8 km/s. Their masses are 0.7x10^4Msun, 5.0x10^4 Msun, 1.6x10^4 Msun, and 0.7x10^4 Msun, respectively. Most are likely associat…
Using the Mopra telescope, we have targeted 61 regions in the Carina Nebula, covering an area of 1.5 square degrees, of bright and compact 870 $μ$m dust continuum emission for molecular line emission from a host of 16 spectral lines at 3mm, including several dense gas tracers. We found that the clumps detected in Carina in general have in average higher temperatures (27 K compared to 21 K), and lower masses (214 M$_\odot$ compared to 508 M$_\odot$) than clumps located at a similar distance to us in the Galactic Plane. We compare the properties of the molecular line emission of these clumps wit…
Context: The Carina Nebula complex (CNC) is one of the most massive and active star-forming regions in our Galaxy and it contains several large young star clusters. The distances of the individual clusters and their physical connection were poorly known up to now, with strongly discrepant results reported in the literature. Aims: We want to determine reliable distances of the young stellar clusters in the central Carina Nebula region (in particular, Tr 14, 15, and 16) and the prominent clusters NGC 3324 and NGC 3293 in the northwestern periphery of the CNC. Methods: We analyzed the parallaxes …
We report high spatial resolution observations of the HI 21cm line in the Carina Nebula and the Gum 31 region obtained with the Australia Telescope Compact Array. The observations covered $\sim$ 12 deg$^2$ centred on $l= 287.5°,b = -1°$, achieving an angular resolution of $\sim $ 35 arcseconds. The HI map revealed complex filamentary structures across a wide range of velocities. Several "bubbles" are clearly identified in the Carina Nebula Complex, produced by the impact of the massive star clusters located in this region. An HI absorption profile obtained towards the strong extragalactic radi…
We report the most detailed $1-3$ GHz radio continuum emission map of the nearest region of massive star formation, the Carina Nebula. As part of a large program with the Australia Telescope Compact Array, we have covered $\sim$ 12 deg$^2$, achieving an angular resolution of $\sim$ 16 arcsec, representing the largest and most complete map of the radio continuum to date. Our continuum map shows a spectacular and complex distribution of emission across the nebula, with multiple structures such as filaments, shells, and fronts across a wide range of size scales. The ionization fronts have advance…
The Carina Nebula harbors a large population of high-mass stars, including at least 75 O-type and Wolf-Rayet stars, but the current census is not complete since further high-mass stars may be hidden in or behind the dense dark clouds that pervade the association. With the aim of identifying optically obscured O- and early B-type stars in the Carina Nebula, we performed the first infrared spectroscopic study of stars in the optically obscured stellar cluster Tr 16-SE, located behind a dark dust lane south of eta Car. We used the integral-field spectrograph KMOS at the ESO VLT to obtain H- and K…
The Carina nebula hosts a large number of globulettes. The majority are of planetary mass, but there are also those with masses of several tens up to a few hundred Jupiter masses. We carried out radio observations of molecular line emission in 12CO and 13CO (2-1) and (3-2) of 12 larger objects in addition of positions in adjacent shell structures using APEX. All selected objects were detected with radial velocities shifted relative to the emission from related shell structures and background molecular clouds. Globulettes along the western part of an extended dust shell show a small spread in v…
We present ALMA high spatial resolution observations towards two star forming regions located in one of the most extreme zones of star formation in the Galaxy, the Carina Nebula. One region is located at the center of the nebula and is severally affected by the stellar feedback from high-mass stars, while the other region is located further south and is less disturbed by the massive star clusters. We found that the region at the center of the nebula is forming less but more massive cores than the region located in the south, suggesting that the level of stellar feedback effectively influence t…
Multi-wavelength observations are mandatory to understand the physical properties of astrophysical sources. In this paper we use observations in the far infrared to radio range to derive the spectral energy distribution (SED) of the Carina nebula. To do this, we carefully subtract the irregularly varying diffuse emission from the Galactic plane, which can be of the order of 10 of the nebula flux at these wavelengths. We find that the far infrared SED can be modeled as emission from a dust population with a single temperature T_d=(34.5^{+2.0}_{-1.8}), and with a spectral index of emissivity alp…
(abbreviated) We used HAWK-I at the ESO VLT to produce a near-infrared survey of the Carina Nebula that is deep enough to detect the full low-mass stellar population. The results of a recent deep X-ray survey are used to distinguish between young stars in Carina and background contaminants. We find that the ages of the low-mass stars (derived from color-magnitude diagrams of the invidual cluster in the Carina Nebula) agree with previous age estimates for the massive stars. About 3200 of the X-ray selected stars have masses >= 1 Msun; this number is in good agreement with extrapolations of the …
Aims: Jets are excellent signposts for very young embedded protostars, so we want to identify jet-driving protostars as a tracer of the currently forming generation of stars in the Carina Nebula, which is one of the most massive galactic star-forming regions and which is characterised by particularly high levels of massive-star feedback on the surrounding clouds. Methods: We used archive data to construct large (> 2 deg x 2 deg) Spitzer IRAC mosaics of the Carina Nebula and performed a spatially complete search for objects with excesses in the 4.5 micron band, typical of shock-excited molecula…
Star cluster complexes such as the Carina Nebula can have formed in turbulent giant molecular clouds. We perform a series of $N$-body simulations starting from subclustering initial conditions based on hydrodynamic simulations of turbulent molecular clouds. These simulations finally result in the formation of star cluster complexes consisting of several subclusters (clumps). We obtain the inter-clump velocity distribution, the size of the region, and the mass of the most massive cluster in our simulated complex and compare the results with observed ones (the Carina Nebula and NGC 2264). The on…
We characterize the stellar population of the poorly explored young stellar cluster NGC 3293 at the northwestern periphery of the Carina Nebula Complex, in order to evaluate the cluster age and the mass function, and to test claims of an abnormal IMF and a deficit of M <= 2.5 M_sun stars. We performed a deep (70 ksec) X-ray observation of NGC 3293 with Chandra and detected 1026 individual X-ray point sources. We identify counterparts for 74% of the X-ray sources in deep near-infrared images. Our data clearly show that NGC 3293 hosts a large population of solar-mass stars, refuting claims of a …
We present new UBVI_C CCD photometry of the young open clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) in the eta Carina nebula. We also identify the optical counterpart of Chandra X-ray sources and Two Micron All Sky Survey point sources. The members of the clusters were selected from the proper motion study, spectral types, reddening characteristics, and X-ray or near-IR excess emission. An abnormal reddening law R_V,cl=4.4\pm0.2 was obtained for the stars in the eta Carina nebula using the 141 early-type stars with high proper motion membership probability (P_u\geq70). We determined th…
Optical and near-infrared images of the Carina Nebula show a peculiar arc-shaped feature, which we call the "Sickle", next to the B-type star Trumpler 14 MJ 218. We use multi-wavelength observations to explore and constrain the nature and origin of the nebulosity. Using sub-mm data from APEX/LABOCA as well as Herschel far-infrared maps, we discovered a dense, compact clump with a mass of ~ 40 Msun located close to the apex of the Sickle. We investigate how the B-star MJ 218, the Sickle, and the clump are related. Our numerical simulations show that, in principle, a B-type star located near the…
We constrain the proper motions of five OB stars associated with candidate stellar wind bow shocks in the Carina Nebula using HST ACS imaging over 9--10 year baselines. These proper motions allow us to directly compare each star's motion to the orientation of its candidate bow shock. Although these stars are saturated in our imaging, we assess their motion by the shifts required to minimize residuals in their Airy rings. The results limit the direction of each star's motion to sectors less than 90 degrees wide. None of the five stars are moving away from the Carina Nebula's central clusters as…
Understanding how the birthplace of stars affects planet-forming discs is important for a comprehensive theory of planet formation. Most stars are born in dense star-forming regions where the external influence of other stars, particularly the most massive stars, will affect the survival and enrichment of their planet-forming discs. Simulations suggest that stellar dynamics play a central role in regulating how external feedback affects discs, but comparing models to observations requires an estimate of the initial stellar density in star-forming regions. Structural analyses constrain the amou…
We present the first extensive spectroscopic study of the global population in star clusters Trumpler~16, Trumpler~14 and Collinder~232 in the Carina Nebula, using data from the Gaia-ESO Survey, down to solar-mass stars. In addition to the standard homogeneous Survey data reduction, a special processing was applied here because of the bright nebulosity surrounding Carina stars. We find about four hundred good candidate members ranging from OB types down to slightly sub-solar masses. About one-hundred heavily-reddened early-type Carina members found here were previously unrecognized or poorly c…
Small molecular cloudlets are abundant in many H II regions surrounding newborn stellar clusters. In optical images these so-called globulettes appear as dark silhouettes against the bright nebular background. We have located close to 300 globulettes in the Carina Nebula. The objects appear as well-confined dense clumps and, as a rule, lack thinner envelopes, bright rims, and tails. Some globulettes are slightly elongated with their major axes oriented in the direction of young clusters in the complex. Many objects are quite isolated and reside at projected distances >1.5 pc from other molecul…
We report high resolution observations of the $^{12}$CO$(1\rightarrow0)$ and $^{13}$CO$(1\rightarrow0)$ molecular lines in the Carina Nebula and the Gum 31 region obtained with the 22-m Mopra telescope as part of the The Mopra Southern Galactic Plane CO Survey. We cover 8 deg$^2$ from $l = 285^{\circ}$ to 290$^{\circ}$, and from $b = -1.5^{\circ}$ to +0.5$^{\circ}$. The molecular gas column density distributions from both tracers have a similar range of values. By fitting a grey-body function to the observed infrared spectral energy distribution from Herschel maps, we derive gas column densiti…
The Great Nebula in Carina is a superb location in which to study the physics of violent massive star-formation and the resulting feedback effects, including cloud dispersal and triggered star-formation. In order to reveal the cold dusty clouds in the Carina Nebula complex, we used the Large APEX Bolometer Camera LABOCA at the APEX telescope to map a 1.25 deg x 1.25 deg (= 50 x 50 pc^2) region at 870 micrometer. From a comparison to Halpha images we infer that about 6% of the 870 micrometer flux in the observed area is likely free-free emission from the HII region, while about 94% of the flux …
We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1--2 km s$^{-1}$ precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile radial velocities from the literature for 32 additional O-type and evolved massive stars in the region. The combined data set shows a mean heliocentric radial velocity of 0.6 km s$^{-1}$. We calculate a velocity dispersion of $\le9.1$ km s$^{-1}$, consist…
Using offset-corrected Gaia-EDR3 parallax measurements and spectrophotometric methods, we have determined distances for 69 massive stars in the Carina OB1 association and associated clusters: Trumpler 16 (21 stars), Trumpler 14 (20 stars), Trumpler 15 (3 stars), Bochum 11 (5 stars), and South Pillars region (20 stars). Past distance estimates to the Carina Nebula range from 2.2 to 3.6 kpc, with uncertainties arising from photometry and anomalous dust extinction. The EDR3 parallax solutions show considerable improvement over DR2, with typical errors $σ_{\varpi}/\varpi \approx$~3-5%. The O-type …
(abbreviated) We investigate the spatial structure and spectral energy distribution of an edge-on circumstellar disk around an optically invisible young stellar object that is embedded in a dark cloud in the Carina Nebula. Whereas the object was detected as an apparently point-like source in earlier infrared observations, only the superb image quality (FWHM ~0.5") of our VLT / HAWK-I data could reveal, for the first time, its peculiar morphology. It consists of a very red point-like central source that is surrounded by a roughly spherical nebula, which is intersected by a remarkable dark lane …
We present the results of analyses of the 12CO (J=1-0), 13CO (J=1-0), and 12CO (J=2-1) emission data toward Gum 31. Three molecular clouds separated in velocity were detected at -25, -20, and -10 km/s . The velocity structure of the molecular clouds in Gum 31 cannot be interpreted as expanding motion. Two of them, the -25 km/s cloud and the -20 km/s cloud, are likely associated with Gum 31, because their 12CO (J=2-1)/12CO (J=1-0) intensity ratios are high. We found that these two clouds show the observational signatures of cloud-cloud collisions (CCCs): a complementary spatial distribution and…
The Carina Nebula represents one of the most massive galactic star forming regions and displays a high level of massive star feedback. We used SPIRE and PACS onboard of Herschel to map the full spatial extent of the clouds in the Carina Nebula complex at wavelengths between 70 and 500 micrometer. We determine color temperatures and column densities of the clouds in the complex. Our Herschel maps show that the clouds have a very complex and filamentary structure that is dominated by the radiation and wind feedback from the massive stars. In most locations, the column density of the clouds is N_…
Infrared observations of the dusty, massive Homunculus Nebula around the luminous blue variable $η$ Carinae are crucial to characterize the mass-loss history and help constrain the mechanisms leading to the Great Eruption. We present the 2.4 - 670 $μ$m spectral energy distribution, constructed from legacy ISO observations and new spectroscopy obtained with the {\em{Herschel Space Observatory}}. Using radiative transfer modeling, we find that the two best-fit dust models yield compositions which are consistent with CNO-processed material, with iron, pyroxene and other metal-rich silicates, coru…
Regions of massive star formation offer some of the best and most easily-observed examples of radiation hydrodynamics. Boundaries where fully-ionized H II regions transition to neutral/molecular photodissociation regions (PDRs) are of particular interest because marked temperature and density contrasts across the boundaries lead to evaporative flows and fluid dynamical instabilities that can evolve into spectacular pillar-like structures. When detached from their parent clouds, pillars become ionized globules that often harbor one or more young stars. H2 molecules at the interface between a PD…
The Carina Nebula represents one of the largest and most active star forming regions known in our Galaxy with numerous very massive stars.Our recently obtained Herschel PACS & SPIRE far-infrared maps cover the full area (about 8.7 deg^2) of the Carina Nebula complex and reveal the population of deeply embedded young stellar objects, most of which are not yet visible in the mid- or near-infrared.We study the properties of the 642 objects that are independently detected as point-like sources in at least two of the five Herschel bands.For those objects that can be identified with apparently singl…
We report the discovery in Hubble Space Telescope (HST) images of the new Herbig-Haro jet, HH 1019, located near the Tr 14 cluster in the Carina Nebula. Like other HH jets in the region, this bipolar collimated flow emerges from the head of a dark dust pillar. However, HH 1019 is unique because -- unlike all other HH jets known to date -- it is identified by a linear chain of dark, dusty knots that are seen primarily in silhouette against the background screen of the H II region. Proper motions confirm that these dark condensations move along the jet axis at high speed. [S II] emission traces …
We present observations from the Gaia-ESO Survey in the lines of H$α$, [N II], [S II] and He I of nebular emission in the central part of the Carina Nebula. We investigate the properties of the two already known kinematic components (approaching and receding, respectively), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV $>$50 km/s) gas emission. We show that gas giving rise to H$α$ and He I emission is dynamically well correlated, but not identical, to gas seen through forbidden-line emission. Gas te…
The Gaia-ESO survey sample of massive OB stars in the Carina Nebula consists of 234 stars. The addition of brighter sources from the Galactic O-Star Spectroscopic Survey and additional sources from the literature allows us to create the most complete census of massive OB stars done so far in the region. It contains a total of 316 stars, being 18 of them in the background and four in the foreground. Of the 294 stellar systems in Car OB1, 74 are of O type, 214 are of non-supergiant B type and 6 are of WR or non-O supergiant (II to Ia) spectral class. We identify 20 spectroscopic binary systems w…
We present proper motion measurements of 37 jets and HH objects in the Carina Nebula measured in two epochs of H$α$ images obtained $\sim 10$ yrs apart with HST/ACS. Transverse velocities in all but one jet are faster than $\gtrsim 25$ km s$^{-1}$, confirming that the jet-like H$α$ features identified by Smith et al. (2010) trace outflowing gas. Proper motions constrain the location of the jet-driving source and provide kinematic confirmation of the intermediate-mass protostars that we identify for 20/37 jets. Jet velocities do not correlate with the estimated protostar mass and embedded drivi…
We report the first results of imaging the Carina Nebula with Spitzer/IRAC, providing a catalog of point sources and YSOs based on SED fits. We discuss several aspects of the extended emission, including dust pillars that result when a clumpy molecular cloud is shredded by massive star feedback. There are few "extended green objects" (EGOs) normally taken as signposts of outflow activity, and none of the HH jets detected optically are seen as EGOs. A population of "extended red objects" tends to be found around OB stars, some with clear bow-shocks. These are dusty shocks where stellar winds co…
We investigate the physical conditions of the CO gas near the young star cluster, Trumpler 14 of the Carina Nebula. The observations presented in this work are taken with the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) onboard the Herschel Space Observatory. Our field of view covers the edge of a cavity carved by Trumpler 14 about $1\,\mathrm{Myr}$ ago and marks the transition from HII regions to photo-dissociation regions. With the state-of-the-art Meudon PDR code, we successfully derive the physical conditions, which include the thermal press…
We performed a deep wide-field (6.76 deg^2) near-infrared survey with the VISTA telescope that covers the entire extent of the Carina nebula complex (CNC). The point-source catalog created from these data contains around four million individual objects down to masses of 0.1 M_sun. We present a statistical study of the large-scale spatial distribution and an investigation of the clustering properties of infrared-excesses objects, which are used to trace disk-bearing young stellar objects (YSOs). We find that a (J - H) versus (Ks - [4.5]) color-color diagram is well suited to tracing the populat…
We want to characterize the properties of the cold dust clumps in the Carina Nebula Complex (CNC), which shows a very high level of massive star feedback. We derive the Clump Mass Function (ClMF), explore the reliability of different clump extraction algorithms, and investigate the influence of the temperatures within the clouds on the resulting shape of the ClMF. We analyze a 1.25x1.25 deg^2 wide-field sub-mm map obtained with LABOCA (APEX), which provides the first spatially complete survey of the clouds in the CNC. We use the three clump-finding algorithms CLUMPFIND (CF), GAUSSCLUMPS (GC) a…
The ionizing radiation of massive stars sculpts the surrounding neutral gas into pillar-like structures. Direct signatures of star formation through outflows and jets are observed in these structures, typically at their tips. Recent numerical simulations have suggested that this star formation could potentially be triggered by photoionising radiation, driving compressive modes of turbulence in the pillars. In this study we use recent high-resolution ALMA observations of $^{12}\mathrm{CO}$, $^{13}\mathrm{CO}$, and $\mathrm{C}^{18} \mathrm{O}, \; J = 2-1$ emission to test this hypothesis for pil…
We present polarimetric observations of the Keyhole Nebula in the Carina Nebula Complex carried out using the Stratospheric Observatory for Infrared Astronomy. The Keyhole Nebula located to the west of $η$ Carinae is believed to be disturbed by the stellar winds from the star. We observed the Keyhole Nebula at 89 $μ$m wavelength with the HAWC+ instrument. The observations cover the entire Keyhole Nebula spanning 8$'$ by 5$'$ with central position RA = 10:44:43 and Dec = -59:38:04. The typical uncertainty of polarization measurement is less than 0.5\% in the region with intensity above 5,500 MJ…
We present a novel infrared spectral energy distribution (SED) modeling methodology that uses likelihood-based weighting of the model fitting results to construct probabilistic H-R diagrams (pHRD) for X-ray identified, intermediate-mass (2-8 $M_{\odot}$), pre-main sequence young stellar populations. This methodology is designed specifically for application to young stellar populations suffering strong, differential extinction ($ΔA_V > 10$ mag), typical of Galactic massive star-forming regions. We pilot this technique in the Carina Nebula Complex (CNC) by modeling the 1-8 $μ$m SEDs of 2269 like…
The massive binary system Eta Carinae and the surrounding HII complex, the Carina Nebula, are potential particle acceleration sites from which very-high-energy (VHE; E > 100 GeV) γ-ray emission could be expected. This paper presents data collected during VHE γ-ray observations with the H.E.S.S. telescope array from 2004 to 2010, which cover a full orbit of Eta Carinae. In the 33.1-hour data set no hint of significant γ-ray emission from Eta Carinae has been found and an upper limit on the γ-ray flux of 7.7 x 10-13 ph cm-2 s-1 (99% confidence level) is derived above the energy threshold of 470 …
We have made mapping observations of L1551 IRS 5, L1551NE, L723, and L43 and single-point observations of IRAS 16293-2422 in the submillimeter CS (J = 7-6) and HCN (J = 4-3) lines with ASTE. Including our previous ASTE observations of L483 and B335, we found a clear linear correlation between the source bolometric luminosities and the total integrated intensities of the submillimeter lines (I_CS ~L_bol^0.92). The combined ASTE + SMA CS (7-6) image of L1551 IRS 5 exhibits an extended (~2000 AU) component tracing the associated reflection nebula at the west and southwest, as well as a compact (<…
A high density portion of the Orion Molecular Cloud 1 (OMC-1) contains the prominent, warm Kleinmann-Low (KL) nebula that is internally powered by an energetic event plus a farther region in which intermediate to high mass stars are forming. Its outside is affected by ultraviolet radiation from the neighboring Orion Nebula Cluster and forms the archetypical photon-dominated region (PDR) with the prominent bar feature. Its nearness makes the OMC-1 core region a touchstone for research on the dense molecular interstellar medium and PDRs. Using the Atacama Pathfinder Experiment telescope (APEX), …
Single-dish sub-millimeter observations have recently revealed the existence of a substantial, chemically peculiar, molecular gas component located in the innermost circumstellar environment of the very massive luminous blue variable star $η$ Carinae. Here, we present 5$"$-resolution interferometric observations of the 1$\rightarrow$0 rotational transition of hydrogen cyanide (HCN) obtained with the Australia Telescope Compact Array (ATCA) toward this star. The emission is concentrated in the central few arcseconds around $η$ Carinae and shows a clear 150 km s$^{-1}$ velocity gradient running …
We present a variety of analyses of the turbulent dynamics of the boundary of a photo-dissociation region (PDR) in the Carina Nebula using high resolution ALMA observations. Using Principal Component Analysis we suggest that the turbulence in this molecular cloud is driven at large scales. Analysis of the centroid velocity structure functions indicate that the turbulence is dominated by shocks rather than local (in k-space) transport of energy. We further find that length-scales in the range 0.02 - 0.03 pc are important in the dynamics of this cloud and this finding is supported by analysis of…
(abridged) Methods: We derive maps of submillimeter dust optical depth and effective dust temperature from Herschel data that were calibrated against Planck. After calibration, we then fit a modified blackbody to the long-wavelength Herschel data, using the Planck-derived dust opacity spectral index beta, derived on scales of 30' (or ~1 pc). We use this model to make predictions of the submillimeter flux density at 850 micron, and we compare these in turn with APEX-Laboca observations. Results: A comparison of the submillimeter dust optical depth and near-infrared extinction data reveals evide…
We report the detection of strong and compact molecular line emission (in the CO J=3-2, 4-3, 6-5, 7-6, 13CO J=3-2, HCN and HCO+ J=4-3 transitions) from a cometary-shaped object (Carina-frEGG1) in the Carina star-forming region (SFR) previously classified as a photoevaporating protoplanetary disk (proplyd). We derive a molecular mass of 0.35 Msun for Carina-frEGG1, which shows that it is not a proplyd, but belongs to a class of free-floating evaporating gas globules (frEGGs) recently found in the Cygnus SFR by Sahai, Morris & Claussen (2012). Archival Adaptive Optics near-IR (Ks) images show a …
In the hierarchical model of structure formation, giant elliptical galaxies form through merging processes within the highest density peaks known as protoclusters. While high-redshift radio galaxies usually pinpoint the location of these environments, we have recently discovered at z~2-3 three Enormous (>200 kpc) Lyman-Alpha Nebulae (ELANe) that host multiple AGN and that are surrounded by overdensities of Lyman-alpha Emitters (LAE). These regions are prime candidates of massive protoclusters in the early stages of assembly. To characterize the star-forming activity within these rare structure…
