Radiative feedback can influence subsequent star formation. We quantify the heating from OB stars in the local star-forming regions in the JCMT Gould Belt survey. Dust temperatures are calculated from 450/850 micron flux ratios from SCUBA-2 observations at the JCMT assuming a fixed dust opacity spectral index $β=1.8$. Mean dust temperatures are calculated for each submillimetre clump along with projected distances from the main OB star in the region. Temperature vs. distance is fit with a simple model of dust heating by the OB star radiation plus the interstellar radiation field and dust cooling through optically thin radiation. Classifying the heating sources by spectral type, O-type stars produce the greatest clump average temperature rises and largest heating extent, with temperatures over 40 K and significant heating out to at least 2.4 pc. Early-type B stars (B4 and above) produce temperatures of over 20 K and significant heating over 0.4 pc. Late-type B stars show a marginal heating effect within 0.2 pc. For a given projected distance, there is a significant scatter in clump temperatures that is due to local heating by other luminous stars in the region, projection effects, or shadowing effects. Even in these local, `low-mass' star-forming regions, radiative feedback is having an effect on parsec scales, with 24% of the clumps heated to at least 3 K above the 15 K base temperature expected from heating by only the interstellar radiation field, and a mean dust temperature for heated clumps of 24 K.
The JCMT Legacy Survey of the Gould Belt: a first look at Serpens with HARP
JCMT上的Gould Belt Legacy Survey（GBS）观测到巨蛇座分子云中12 CO J=3- 2发射的260平方角分区域，以及13 CO和C18 O发射的190平方角分子集。我们研究了非流出气体的全局速度结构，并计算了激发温度和不透明度。大规模的质量和能量的区域进行评估，特别考虑到高速气体。我们发现这个云的质量是203个太阳质量，并且受到引力束缚，流出气体的动能大约是云湍流动能的70%。我们确定了该地区一些亚毫米级0/I类源的紧凑流出
The distribution of ultraviolet (UV) radiation field provides critical constraints on the physical environments of molecular clouds. Within 1 kpc of our solar system and fostering protostars of different masses, the giant molecular clouds in the Gould Belt present an excellent opportunity to resolve the UV field structure in star forming regions. We performed spectral energy distribution (SED) fitting of the archival data from the Herschel Gould Belt Survey (HGBS). Dust radiative transfer analysis with the DUSTY code were applied to 23 regions in 14 molecular complexes of the Gould Belt, resul…
We analyze the spatial and kinematic properties of a large sample of young T Tauri type stars in a 500 pc radius solar neighborhood, closely related to the Gould belt. The following parameters of the exponential density distribution have been determined: the average $(z_G)_\odot=-25\pm5$ pc and scale height $h_G=56\pm6$ pc. We propose a method of excluding background stars from the samples, which are located at large heights with respect to the symmetry plane of the Gould belt. We discovered that the expansion effect for the entire star system, $K_G=6\pm1$ km s$^{-1}$ kpc$^{-1}$, is determined…
The distribution of sites where globular clusters have crossed the Galactic disk during the last 100 million years has been analyzed using the most recent kinematic data for 133 globular clusters (GCs). Three GCs (NGC 6341, NGC 7078, and $ω$ Cen) whose distances between the positions where they crossed the Galactic disk and trajectories of the Gould Belt are less than 20\% of their heliocentric distances at the crossing time (82, 98, and 96 million years ago, respectively) have been identified. For each of the clusters, this was their next to last, rather than their last, crossing of the Galac…
The JCMT Transient Survey: Identifying Submillimetre Continuum Variability over Several Year Timescales Using Archival JCMT Gould Belt Survey Observations
We present a subset of the James Clerk Maxwell Telescope Gould Belt Survey's "first-look" results of the southern extent of the Orion A molecular cloud. Employing a two-step structure identification process, we constructed individual catalogues for large-scale regions of significant emission labeled as "islands" and smaller-scale subregions called "fragments" using the 850 $μ$m continuum maps obtained using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2). We highlight the relationship between the concentration and Jeans stability for regions of significant emission and present the re…
The JCMT Gould Belt Survey: First results from the Corona Australis molecular cloud and evidence of variable dust emissivity indices in the Coronet region
The JCMT Gould Belt Survey was one of the first Legacy Surveys with the James Clerk Maxwell Telescope in Hawaii, mapping 47 square degrees of nearby (< 500 pc) molecular clouds in both dust continuum emission at 850 $μ$m and 450 $μ$m, as well as a more-limited area in lines of various CO isotopologues. While molecular clouds and the material that forms stars have structures on many size scales, their larger-scale structures are difficult to observe reliably in the submillimetre regime using ground-based facilities. In this paper, we quantify the extent to which three subsequent data-reduction …
In this paper the results of matching the RAdial Velocity Experiment (RAVE), a spectroscopic Southern hemisphere survey (9 $ < I_{DENIS} <$ 12), and XMM-Newton Serendipitous Source Catalogue (3XMM) are presented. The latest data releases of RAVE and XMM were matched and a X-ray RAVE catalogue of 1071 stars was obtained. Then the catalogue was checked for possible Gould Belt (GB) members. We obtained a subsample of 10 stars that meet the GB membership criteria. This subsample and GB member candidates were tested photometrically and kinematically. Among the members there are two BY Dra type vari…
We present 850 and 450 micron observations of the dense regions within the Auriga-California molecular cloud using SCUBA-2 as part of the JCMT Gould Belt Legacy Survey to identify candidate protostellar objects, measure the masses of their circumstellar material (disk and envelope), and compare the star formation to that in the Orion A molecular cloud. We identify 59 candidate protostars based on the presence of compact submillimeter emission, complementing these observations with existing Herschel/SPIRE maps. Of our candidate protostars, 24 are associated with young stellar objects (YSOs) in …
The Link between Magnetic Fields and Filamentary Clouds: Bimodal Cloud Orientations in the Gould Belt
利用近红外尘埃消光图和光学恒星偏振计资料研究了古尔德带内的对流分子云及其局部ICM（云间介质）磁场的方向。这些对流云的长度在几秒差距到十秒差距之间，我们发现它们的方向倾向于平行或垂直于当地ICM的平均场方向。这种双峰分布是没有发现在云模拟与超Alfvenic湍流，云的方向应该是随机的。ICM磁场在动力学上比惯性范围的湍流和自引力更重要，它可以很容易地解释这两种场丝结构。以前的研究普遍认为，强磁场可以引导引力收缩，并导致纤维垂直于他们，但很少讨论的事实，磁场也可以通道亚阿尔芬湍流，形成与他们对齐的纤维。这种云形成的强场情景也与从ICM到云观测到的恒定场强相一致（Crutcher et al. 2010），并且可以解释“中心-细丝”云结构（Myers 2009）和云重力收缩的密度阈值（Kainulainen et al. 2009）。
We present an analysis of the astrometric results from Gaia second data release (DR2) to Young Stellar Objects (YSOs) in star-forming regions related to the Gould Belt. These regions are Barnard 59, Lupus 1 to 4, Chamaeleon I and II, $ε$-Chamaeleontis, the Cepheus flare, IC 5146 and Corona Australis. The mean distance to the YSOs in each region are consistent with earlier estimations, though a significant improvement to the final errors was obtained. The mean distances to the star-forming regions were used to fit an ellipsoid of size $(358\pm7)\times(316\pm13)\times(70\pm4)$ pc, and centered a…
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…
The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
在本文中，我们提出了第一次观测的蛇夫座分子云的詹姆斯克拉克麦克斯韦望远镜（JCMT）古尔德带调查（GBS）的一部分，与SCUBA-2仪器。我们展示了将这些数据与以前的HARP CO，Herschel和IRAM N $_{2}$ H $^{+}$观测相结合的方法，以准确地量化蛇夫座SCUBA-2源的特性。我们制作了一份SCUBA-2发现的所有来源的目录。我们把它们分成原恒星和无恒星的核心。我们列出了所有的无星核心，并进行了全面的维里分析，包括外部压力。这是第一次将外部压力包括在这一详细程度中。我们发现我们的大多数核心要么是束缚的，要么是男性化的。引力能和外压的平均值在数量级上是相似的，但各区域之间有一些差异。我们发现，在OPH A区域的核心是重力约束的星前核心，而在OPH C和E区域的核心是压力限制。我们确定，N $_{2}$ H $^{+}$是一个很好的示踪剂的结合材料的星前核心，虽然我们发现了一些证据N $_{2}$ H $^{+}$冻结在非常高的核心密度。我们发现，非热线宽之间的跟踪由C $^{18}$ O和跟踪由N $_{2}$ H $^{+}$，表明在较高的密度湍流耗散的气体大幅减少。我们发现，临界Bonnor-Ebert稳定性准则是不是一个很好的指标，我们的核心的有界性。我们探测到前褐矮星候选者Oph B-11，并发现与以前的工作一致的通量密度和质量。我们讨论的核心的性质…
We present a catalogue of prestellar and starless cores within the Corona Australis molecular cloud using photometric data from the Herschel Space Observatory. At a distance of d~130 pc, Corona Australis is one of the closest star-forming regions. Herschel has taken multi-wavelength data of Corona Australis with both the SPIRE and PACS photometric cameras in a parallel mode with wavelengths in the range 70 μm to 500 μm. A complete sample of starless and prestellar cores and embedded protostars is identified. Other results from the Herschel Gould Belt Survey have shown spatial correlation betwe…
Dynamical studies of dense structures within molecular clouds often conclude that the most massive clumps contain too little kinetic energy for virial equilibrium, unless they are magnetized to an unexpected degree. This raises questions about how such a state might arise, and how it might persist long enough to represent the population of massive clumps. In an effort to re-examine the origins of this conclusion, we use ammonia line data from the Green Bank Ammonia Survey and Planck-calibrated dust emission data from Herschel to estimate the masses and kinetic and gravitational energies for de…
The Herschel Gould Belt Survey key project mapped the bulk of nearby star-forming molecular clouds in five far-infrared bands with the aim of compiling complete census of prestellar cores and young, embedded protostars. In this paper, we present the catalogue of the dense cores and YSOs/protostars extracted from the Herschel maps of the Lupus I, III, and IV molecular clouds. The physical properties of the detected objects were derived by fitting their spectral energy distributions. A total of 532 dense cores, out of which 103 are presumably prestellar in nature, and 38 YSOs/protostars have bee…
We analyse an all-sky compilation of thirteen data sources with optical interstellar linear polarisation for 3871 {\it Gaia} DR2 and {\it Hipparcos} stars within 500 pc, which do not exhibit a considerable intrinsic polarisation. These data are analysed together with five 3D maps and models of the reddening $E(B-V)$. We consider variations of the polarisation degree $P$, position angle $θ$, and polarisation efficiency $P/E(B-V)$ with Galactic coordinates, distance $R$, and dereddened colour. $P$ shows a maximum at the Gould Belt mid-plane. $P/R$ drops in the Local Bubble by several times defin…
