We present submillimetre observations of the J = 3-2 rotational transition of 12CO, 13CO and C18O across over 600 sq arcmin of the Perseus molecular cloud, undertaken with HARP, a new array spectrograph on the James Clerk Maxwell Telescope. The data encompass four regions of the cloud, containing the largest clusters of dust continuum condensations: NGC 1333, IC348, L1448 and L1455. A new procedure to remove striping artefacts from the raw HARP data is introduced. We compare the maps to those of the dust continuum emission mapped with SCUBA (Hatchell et al. 2005) and the positions of starless and protostellar cores (Hatchell et al. 2007a). No straightforward correlation is found between the masses of each region derived from the HARP CO and SCUBA data, underlining the care that must be exercised when comparing masses of the same object derived from different tracers. From the 13CO/C18O line ratio the relative abundance of the two species ([13CO]/[C18O] ~ 7) and their opacities (typically tau is 0.02-0.22 and 0.15-1.52 for the C18O and 13CO gas respectively) are calculated. C18O is optically thin nearly everywhere, increasing in opacity towards star-forming cores but not beyond tau(C18O)~0.9. Assuming the 12CO gas is optically thick we compute its excitation temperature (around 8-30 K), which has little correlation with estimates of the dust temperature.
We present a census of molecular outflows across four active regions of star formation in the Perseus molecular cloud (NGC 1333, IC348/HH211, L1448 and L1455), totalling an area of over 1000 sq arcmin. This is one of the largest surveys of outflow evolution in a single molecular cloud published to date. We analyse large-scale, sensitive CO J=3-2 datasets from the James Clerk Maxwell Telescope, including new data towards NGC 1333. Where possible we make use of our complementary 13CO and C18O data to correct for the 12CO optical depth and measure ambient cloud properties. Of the 65 submillimetre…
We explore the kinematics of continuum clumps in the Perseus molecular cloud, derived from C18O J=3-2 data. Two populations are examined, identified using the automated algorithms CLFIND and GAUSSCLUMPS on existing SCUBA data. The clumps have supersonic linewidths with distributions which suggest the C18O line probes a lower-density 'envelope' rather than a dense inner core. Similar linewidth distributions for protostellar and starless clumps implies protostars do not have a significant impact on their immediate environment. The proximity to an active young stellar cluster seems to affect the …
We present ammonia maps of portions of the W3 and Perseus molecular clouds in order to compare gas emission with submillimetre continuum thermal emission which are commonly used to trace the same mass component in star-forming regions, often under the assumption of LTE. The Perseus and W3 star-forming regions are found to have significantly different physical characteristics consistent with the difference in size scales traced by our observations. Accounting for the distance of the W3 region does not fully reconcile these differences, suggesting that there may be an underlying difference in th…
An updated model for the Perseus Spiral Arm from Trigonometric Parallax and 3-dimensional kinematic distances of distant massive stars
University of Tasmania（塔斯马尼亚大学）；International Centre for Radio Astronomy Research, The University of Western Australia（西澳大利亚大学国际射电天文研究中心）；Nanjing University（南京大学）
We present results of a survey of 14 star-forming regions from the Perseus spiral arm in CS(2-1) and 13CO(1-0) lines with the Onsala Space Observatory 20 m telescope. Maps of 10 sources in both lines were obtained. For the remaining sources a map in just one line or a single-point spectrum were obtained. On the basis of newly obtained and published observational data we consider the relation between velocities of the "quasi-thermal" CS(2-1) line and 6.7 GHz methanol maser line in 24 high-mass star-forming regions in the Perseus arm. We show that, surprisingly, velocity ranges of 6.7 GHz methan…
We present continuum observations of the Perseus B1-E region from the Herschel Gould Belt Survey. These Herschel data reveal a loose grouping of substructures at 160 - 500 micron not seen in previous submillimetre observations. We measure temperature and column density from these data and select the nine densest and coolest substructures for follow-up spectral line observations with the Green Bank Telescope. We find that the B1-E clump has a mass of ~ 100 solar masses and appears to be gravitationally bound. Furthermore, of the nine substructures examined here, one substructure (B1-E2) appears…
We derive the distance and structure of the Perseus molecular cloud by combining trigonometric parallaxes from Very Long Baseline Array (VLBA) observations, taken as part of the GOBELINS survey, and Gaia Data Release 2. Based on our VLBA astrometry, we obtain a distance of 321+/-10 pc for IC 348. This is fully consistent with the mean distance of 320+/-26 measured by Gaia. The VLBA observations toward NGC 1333 are insufficient to claim a successful distance measurement to this cluster. Gaia parallaxes, on the other hand, yield a mean distance of 293+/-22 pc. Hence, the distance along the line …
We use the Sternberg et al. (2014) theory for interstellar atomic to molecular (HI-to-H$_2$) conversion to analyze HI-to-H$_2$ transitions in five (low-mass) star-forming and dark regions in the Perseus molecular cloud, B1, B1E, B5, IC348, and NGC1333. The observed HI mass surface densities of 6.3 to 9.2 M$_{\odot}$ pc$^{-2}$ are consistent with HI-to-H$_2$ transitions dominated by HI-dust shielding in predominantly atomic envelopes. For each source, we constrain the dimensionless parameter $αG$, and the ratio $I_{\rm UV}/n$, of the FUV intensity to hydrogen gas density. We find $αG$ values fr…
The kinematics of the outer rings and pseudorings is determined by two processes: the resonance tuning and the gas outflow. The resonance kinematics is clearly observed in the pure rings, while the kinematics of the gas outflow is manifested itself in the pseudorings. The direction of systematical motions in the pure rings depends on the position angle of a point with respect to the bar major axis and on the class of the outer ring. The direction of the radial and azimuthal components of the residual velocities of young stars in the Perseus, Carina, and Sagittarius regions can be explained by …
Mapping the Perseus Galaxy Cluster with XRISM: Gas Kinematic Features and their Implications for Turbulence
Masaryk University（马萨里克大学）；The University of Chicago（芝加哥大学）；Center for Astrophysics | Harvard-Smithsonian（哈佛-史密森天体物理中心）；University of Maryland, Baltimore County (UMBC)（马里兰大学巴尔的摩分校）；NASA / Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理学研究所）；Space Research Institute (IKI)（空间研究所）；Lawrence Livermore National Laboratory（劳伦斯利弗莫尔国家实验室）；Tokyo Metropolitan University（东京都立大学）；Université de Montréal（蒙特利尔大学）
We present a comprehensive analysis on the evolution of envelopes surrounding protostellar systems in the Perseus molecular cloud using data from the MASSES survey. We focus our attention to the C$^{18}$O(2--1) spectral line, and we characterize the shape, size, and orientation of 54 envelopes and measure their fluxes, velocity gradients, and line widths. To look for evolutionary trends, we compare these parameters to the bolometric temperature Tbol, a tracer of protostellar age. We find evidence that the angular difference between the elongation angle of the C$^{18}$O envelope and the outflow…
We present ALMA observations of the mid-J 12CO emission from six single-dish selected 870-micron sources in the Extended Chandra Deep Field-South (ECDFS) and UKIDSS Ultra-Deep Survey (UDS) fields. These six single-dish submillimetre sources were selected based on previous ALMA continuum observations, which showed that each comprised a blend of emission from two or more individual submillimetre galaxies (SMGs), separated on 5--10 arcsec scales. The six single-dish submillimetre sources targeted correspond to a total of 14 individual SMGs, of which seven have previously-measured robust optical/n…
We utilize the extensive datasets available for the Perseus molecular cloud to analyze the relationship between the kinematics of small-scale dense cores and the larger structures in which they are embedded. The kinematic measures presented here can be used in conjunction with those discussed in our previous work as strong observational constraints that numerical simulations (or analytic models) of star formation should match. We find that dense cores have small motions with respect to the 13CO gas, about one third of the 13CO velocity dispersion along the same line of sight. Within each extin…
We present H13CO+ (J=1-0) and HNC (J=1-0) maps of regions in Serpens South, Serpens Main and NGC 1333 containing filaments. We also observe the Serpens regions using H13CN (J=1-0). These dense gas tracer molecular line observations carried out with CARMA have an angular resolution of ~7", a spectral resolution of ~0.16 km/s and a sensitivity of 50-100 mJy/beam. Although the large scale structure compares well with the Herschel dust continuum maps, we resolve finer structure within the filaments identified by Herschel. The H13CO+ emission distribution agrees with the existing CARMA N2H+ (J=1-0)…
Observations of the dust emission using millimetre/submillimetre bolometer arrays can be contaminated by molecular line flux, such as flux from 12CO. As the brightest molecular line in the submillimetre, it is important to quantify the contribution of CO flux to the dust continuum bands. Conversion factors were used to convert molecular line integrated intensities to flux detected by bolometer arrays in mJy per beam. These factors were calculated for 12CO line integrated intensities to the SCUBA-2 850 μm and 450 μm bands. The conversion factors were then applied to HARP 12CO 3-2 maps of NGC 13…
We introduce a new kinematic method to investigate the structure of open star clusters. We adopt a hierarchical clustering algorithm that uses the celestial coordinates and the proper motions of the stars in the field of view of the cluster to estimate a proxy of the pairwise binding energy of the stars and arrange them in a binary tree. The cluster substructures and their members are identified by trimming the tree at two thresholds, according to the $σ$-plateau method. Testing the algorithm on 100 mock catalogs shows that, on average, the membership of the identified clusters is $(91.5\pm 3.…
Context. Star-forming regions are excellent benchmarks for testing and validating theories of star formation and stellar evolution. The Perseus star-forming region being one of the youngest (<10 Myr), closest (280-320 pc), and most studied in the literature, is a fundamental benchmark. Aims. We aim to study the membership, phase-space structure, mass, and energy (kinetic plus potential) distribution of the Perseus star-forming region using public catalogues (Gaia, APOGEE, 2MASS, PanSTARRS). Methods. We use Bayesian methodologies accounting for extinction to identify the Perseus physical groups…
We present the results of a large-scale survey of the very dense gas in the Perseus molecular cloud using HCO+ and HCN (J = 4 - 3) transitions. We have used this emission to trace the structure and kinematics of gas found in pre- and protostellar cores, as well as in outflows. We compare the HCO+/HCN data, highlighting regions where there is a marked discrepancy in the spectra of the two emission lines. We use the HCO+ to identify positively protostellar outflows and their driving sources, and present a statistical analysis of the outflow properties that we derive from this tracer. We find tha…
We present the first results from our on-going Australia Telescope Compact Array survey of CO(1-0) in ALMA-identified submillimetre galaxies in the Extended Chandra Deep Field South. Strong detections of CO(1-0) emission from two submillimetre galaxies, ALESS 122.1 (z = 2.0232) and ALESS 67.1 (z = 2.1230), were obtained. We estimate gas masses of M_gas ~ 1.3 \times 10^{11} M_odot and M_gas ~ 1.0 \times 10^{11} M_\odot for ALESS 122.1 and ALESS 67.1, respectively, adopting alpha_CO = 1.0. Dynamical mass estimates from the kinematics of the CO(1-0) line yields M_dyn (sin i)^2 = 2.1 +- 1.1 \times…
Large-scale surveys of the Perseus molecular cloud have provided many clues as to the processes occurring during star formation. Here, analysis of both column density maps and kinematic data (maps and pointed data) are discussed and compared with predictions from simulations. Results include a column density threshold for the formation of dense star-forming cores and that the dense cores are quiescent within their local environment, while the molecular cloud as a whole has turbulent motions that are dominated by large-scale modes. Some of these results have already been used to constrain model…
We use photometric and kinematic data from Gaia DR2 to explore the structure of the star forming region associated with the molecular cloud of Perseus. Apart from the two well known clusters, IC 348 and NGC 1333, we present five new clustered groups of young stars, which contain between 30 and 300 members, named Autochthe, Alcaeus, Heleus, Electryon and Mestor. We demonstrate these are co-moving groups of young stars, based on how the candidate members are distributed in position, proper motion, parallax and colour-magnitude space. By comparing their colour-magnitude diagrams to isochrones we …
We report the discovery of substellar objects in the young star cluster IC 348 and the neighboring Barnard 5 dark cloud, both at the eastern end of the Perseus star-forming complex. The substellar candidates are selected using narrowband imaging, i.e., on and off photometric technique with a filter centered around the water absorption feature at 1.45 microns, a technique proven to be efficient in detecting water-bearing substellar objects. Our spectroscopic observations confirm three brown dwarfs in IC 348. In addition, the source WBIS 03492858+3258064, reported in this work, is the first conf…
Kinematic distances to 750 molecular clouds identified in the 13CO J=1-0 Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey (BU-FCRAO GRS) are derived assuming the Clemens rotation curve of the Galaxy. The kinematic distance ambiguity is resolved by examining the presence of HI self-absorption toward the 13CO emission peak of each cloud using the Very Large Array Galactic Plane Survey (VGPS). We also identify 21 cm continuum sources embedded in the GRS clouds in order to use absorption features in the HI 21 cm continuum to distinguish between near and far kinematic…
Using of a new N-body simulation, as well as Gaia DR2/EDR3 data complemented by data from the Galah, APOGEE, LAMOST surveys, we explore the possible link between the MW spiral arms, RVphi-ridges and moving groups in local UV space. We show that the tightly wound main spiral arms in the N-body model can be successfully identified using overdensities in angular momentum (AM) or guiding space, as well as in the distribution of dynamically cold stars close to their guiding centers. Stars in the AM overdensities that travel over many kpc in radius trace extended density ridges in RVphi space and ov…
We present the first dust emission results toward a sample of seven protostellar disk candidates around Class 0 and I sources in the Perseus molecular cloud from the VLA Nascent Disk and Multiplicity (VANDAM) survey with ~0.05'' or 12 AU resolution. To examine the surface brightness profiles of these sources, we fit the Ka-band 8 mm dust-continuum data in the u,v-plane to a simple, parametrized model based on the Shakura-Sunyaev disk model. The candidate disks are well-fit by a model with a disk-shaped profile and have masses consistent with known Class 0 and I disks. The inner-disk surface de…
We analyze the internal dynamics of young stars towards Perseus using Gaia EDR3 data, including Per OB2 and California Cloud. Interpreting the current dynamics, we speculate that Per OB2 may have formed from two separate clouds that have begun forming stars in a close proximity of each other. IC 348 is caught in the middle between the two of them, inheriting kinematics of both, and it stands out as a possible site of cloud cloud interaction. We also consider a possibility of a past supernova in Per OB2 - while one had likely occurred, it did not appear to have caused any obvious triggered star…
In order to study the streaming motions of miras in the Solar neighborhood, we newly surveyed 379 red variables in the SiO maser lines at 42.821 and 43.122 GHz with the Nobeyama 45m radio telescope. Accurate radial velocities were obtained for 229 (220 new) detected stars. The sample is selected from optical variables found by new automated surveys: the Northern Sky Variability Survey and the All Sky Automated Survey. The new sample consists of the "bluer" objects compared with those observed in the previous SiO surveys. The distances to the objects are estimated using the period-luminosity re…
We report the detection of CO(1-0) emission from NGC 1277, a lenticular galaxy in the Perseus Cluster. NGC 1277 has previously been proposed to host an overmassive black hole (BH) compared to the galaxy bulge luminosity (mass), based on stellar-kinematic measurements. The CO(1-0) emission, observed with the IRAM Plateau de Bure Interferometer (PdBI) using both, a more compact (2.9-arcsec resolution) and a more extended (1-arcsec resolution) configuration, is likely to originate from the dust lane encompassing the galaxy nucleus at a distance of 0.9 arcsec (~320 pc). The double-horned CO(1-0) p…
We present an expanded distance catalog for 1,710 molecular cloud structures identified in the Bolocam Galactic Plane Survey (BGPS) version 2, representing a nearly threefold increase over the previous BGPS distance catalog. We additionally present a new method for incorporating extant data sets into our Bayesian distance probability density function (DPDF) methodology. To augment the dense-gas tracers (e.g., HCO+(3-2), NH3(1,1)) used to derive line-of-sight velocities for kinematic distances, we utilize the Galactic Ring Survey 13CO(1-0) data to morphologically extract velocities for BGPS sou…
High-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array have been used to trace the kinematics of the molecular gas in the Seyfert 2 galaxy{IC~5063}. Although one of the most radio-loud Seyfert galaxy, IC~5063 is a relatively weak radio source (P_1.4GHz = 3 x 10^23 W Hz^-1). The data reveal that the kinematics of the gas is very complex. A fast outflow of molecular gas extends along the entire radio jet (~ 1 kpc), with the highest outflow velocities about 0.5 kpc from the nucleus, at the location of the brighter hot-spot in the W lobe. …
G351.776-0.527 is among the most massive, closest, and youngest filaments in the inner Galactic plane and therefore it is an ideal laboratory to study the kinematics of dense gas and mass replenishment on a large scale. In this paper, we present far-infrared (FIR) and submillimetre wavelength continuum observations combined with spectroscopic C$^{18}$O (2-1) data of the entire region to study its temperature, mass distribution, and kinematics. The structure is composed of a main elongated region with an aspect ratio of $\sim 23$, which is associated with a network of filamentary structures. Th…
New star clusters discovered towards the Galactic anticentre direction using Gaia DR3 data
Universidade Federal de Minas Gerais（米纳斯吉拉斯联邦大学）；Centro Federal de Educação Tecnológica de Minas Gerais（米纳斯吉拉斯州联邦技术教育中心）；Laboratório Nacional de Astrofísica LNA（国家天体物理实验室）
We present spatial and kinematic correlation between the young stellar population and the cloud clumps in the Ophiuchus star-forming region. The stellar sample consists of known young objects at various evolutionary stages, taken from the literature, some of which are diagnosed with Gaia EDR3 parallax and proper-motion measurements. The molecular gas is traced by the 850 $μ$m Submillimetre Common-User Bolometer Array-2 image, reaching $\sim$2.3 mJy beam$^{-1}$, the deepest so far for the region, stacked from the James Clerk Maxwell Telescope/Transient program aiming to detect submillimeter out…
We report the results of high spatial and spectral resolution integral-field spectroscopy of the central ~3 x 3 arcsec^2 of the active galaxy NGC 1275 (Perseus A), based on observations with the Near-infrared Integral Field Spectrograph (NIFS) and the ALTAIR adaptive-optics system on the Gemini North telescope. The circum-nuclear disc in the inner R~50 pc of NGC 1275 is seen in both the H2 and [FeII] lines. The disc is interpreted as the outer part of a collisionally-excited turbulent accretion disc. The kinematic major axis of the disc at a position angle of 68 deg is oriented perpendicular t…
We perform a virial analysis of starless dense cores in three nearby star-forming regions : L1688 in Ophiuchus, NGC 1333 in Perseus, and B18 in Taurus. Our analysis takes advantage of comprehensive kinematic information for the dense gas in all of these regions made publicly available through the Green Bank Ammonia Survey Data Release 1, which used to estimate internal support against collapse. We combine this information with ancillary data used to estimate other important properties of the cores, including continuum data from the James Clerk Maxwell Telescope Gould Belt Survey for core ident…
We present details of the CARMA Large Area Star Formation Survey (CLASSy), while focusing on observations of Barnard 1. CLASSy is a CARMA Key Project that spectrally imaged N2H+, HCO+, and HCN (J=1-0 transitions) across over 800 square arcminutes of the Perseus and Serpens Molecular Clouds. The observations have angular resolution near 7" and spectral resolution near 0.16 km/s. We imaged ~150 square arcminutes of Barnard 1, focusing on the main core, and the B1 Ridge and clumps to its southwest. N2H+ shows the strongest emission, with morphology similar to cool dust in the region, while HCO+ a…
The trigonometric parallax of IRAS 23385+6053 and physical properties of molecular clouds based on the VLBI astrometry
Graduate School of Science and Engineering, Kagoshima University（鹿儿岛大学理工学研究科）；Curatorial division, Nagoya City Science Museum（名古屋市科学馆策展部）；Department of Physics, Graduate School of Science, Nagoya University（名古屋大学理学研究科物理学科）；National Astronomical Research Institute of Thailand (Public Organization)（泰国国家天文研究所）；Mizusawa VLBI Observatory, National Astronomical Observatory of Japan（日本国立天文台水泽VLBI观测站）；Astrobiology Center（天体生物学中心）；National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS)（日本国立天文台（NAOJ），国立自然科学研究院（NINS））
Unresolved gas and dust observations show a surprising diversity in the amount of interstellar matter in early-type galaxies. Using ALMA observations we resolve the ISM in z$\sim$0.05 early-type galaxies. From a large sample of early-type galaxies detected in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) we selected five of the dustiest cases, with dust masses M$_d\sim$several$\times10^7$M$_\odot$, with the aim of mapping their submillimetre continuum and $^{12}$CO(2-1) line emission distributions. These observations reveal molecular gas disks. There is a lack of associated,…
The aim of this study is to better understand the physical and chemical properties of the filamentary IRDC G304.74+01.32. In particular, we aim to investigate the kinematics and dynamical state of the cloud and clumps within it, and the amount of CO depletion. All the submillimetre peak positions in the cloud identified from our previous LABOCA 870-micron map were observed in C17O(2-1) with APEX. Selected positions were also observed in the 13CO(2-1), SiO(5-4), and CH3OH(5_k-4_k) transitions at ~1 mm wavelength. The C17O lines were detected towards all target positions at similar radial veloci…
Investigating the role of turbulence in the interstellar medium in $z\sim3$ dusty star-forming galaxies using kpc-resolution ALMA dust and gas maps
Leiden University（莱顿大学）；Delft University of Technology（代尔夫特理工大学）；SRON – Netherlands Institute for Space Research（荷兰空间研究所）；University of Western Australia（西澳大学）；Australian National University（澳大利亚国立大学）；Durham University（杜伦大学）
We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 μm, 160 μm, 250 μm, 350 μm, and 500 μm by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Herschel Space Observatory as part of the Herschel imaging survey of OB young stellar objects (HOBYS) Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In ad…
The analysis of large molecular line surveys of the Galactic plane is essential for our understanding of the gas kinematics on Galactic scales, in particular its link with the formation and evolution of dense structures in the interstellar medium. An approximation of the emission peaks with Gaussian functions allows for an efficient and straightforward extraction of useful physical information contained in the shape and Doppler-shifted frequency of the emission lines contained in these enormous data sets. In this work we present an overview and first results of a Gaussian decomposition of the …
By positional matching to the catalogue of Galactic Ring Survey molecular clouds, we have derived distances to 793 Bolocam Galactic Plane Survey (BGPS) sources out of a possible 806 located within the region defined by Galactic longitudes l = 28.5 degr to 31.5 degr and latitudes |b| < 1 degr. This section of the Galactic Plane contains several major features of Galactic structure at different distances, mainly mid-arm sections of the Perseus and Sagittarius spiral arms and the tangent of the Scutum-Centarus arm, which is coincident with the end of the Galactic Long Bar. By utilising the catalo…
We present an overview of the first data release (DR1) and first-look science from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green Bank Telescope to map all Gould Belt star-forming regions with $A_V \gtrsim 7$ mag visible from the northern hemisphere in emission from NH$_3$ and other key molecular tracers. This first release includes the data for four regions in Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and Orion A North in Orion. We compare the NH$_3$ emission to dust continuum emission from Herschel, and find that the two tracers corr…
