Glue

Catherine Zucker

and 2 more

Recently, argued that a very long, very thin infrared dark cloud “Nessie” lies directly in the Galactic midplane and runs along the Scutum-Centaurus arm in position-position-velocity (p-p-v) space as traced by lower density CO and higher density NH₃ gas. Nessie was presented as the first “bone” of the Milky Way, an extraordinarily long, thin, high contrast filament that can be used to map our galaxy’s ”skeleton.“ We present the first evidence of additional bones in the Milky Way Galaxy, arguing that Nessie is not a curiosity but one of several filaments that could potentially trace Galactic structure. Our ten bone candidates are all long, filamentary, mid-infrared extinction features which lie parallel to, and no more than twenty parsecs from, the physical Galactic midplane. We use CO, N₂H+, HCO+ and NH₃ radial velocity data to establish the location of the candidates in p-p-v space. Of the ten filaments, six candidates also have a projected aspect ratio of ≥50: 1, run along, or extremely close to, the Scutum-Centaurus arm in p-p-v space, and exhibit no abrupt shifts in velocity. Evidence suggests that these candidates are Nessie-like filaments which mark the location of significant spiral features, with ”filament 5" replicating Nessie’s properties most strongly. As molecular spectral-line and extinction maps cover more of the sky at increasing resolution and sensitivity, we seek to find more bones in future studies, ultimately to create a global-fit to the Galaxy’s spiral arms by piecing together individual skeletal features.
Skeleton new

Catherine Zucker

and 2 more

Recently, argued that the very long, very thin infrared dark cloud “Nessie” lies directly in the Galactic midplane and runs along the Scutum-Centaurus arm in position-position-velocity (_p-p-v_) space as traced by lower density CO and higher density NH₃ gas. Nessie was presented as the first “bone” of the Milky Way, an extraordinarily long, thin, high-contrast filament that can be used to map our Galaxy’s ”skeleton.“ Here, we present evidence for additional bones in the Milky Way Galaxy, arguing that Nessie is not a curiosity but one of several filaments that could potentially trace Galactic structure. Our ten bone candidates are all long, filamentary, mid-infrared extinction features which lie parallel to, and no more than twenty parsecs from, the physical Galactic mid-plane. We use CO, N₂H+, HCO+ and NH₃ radial velocity data to establish the three-dimensional location of the candidates in _p-p-v_ space. Of the ten candidates, six also: have a projected aspect ratio of ≥50: 1; run along, or extremely close to, the Scutum-Centaurus arm in _p-p-v_ space; _and_ exhibit no abrupt shifts in velocity. Evidence suggests that these candidates are marking the locations of significant spiral features, with the bone called filament 5 (”BC_18.88-0.09") being a close analog to Nessie in the Northern Sky. As molecular spectral-line and extinction maps cover more of the sky at increasing resolution and sensitivity, we seek to find more bones in future studies, ultimately to create a global-fit to the Galaxy’s spiral arms by piecing together individual skeletal features.
Example

Francesca Childs

and 1 more

Internet technologies make it easier and easier to share data globally, enabling a dramatic proliferation of online “citizen science” projects. One new project, called “oldAstronomy,” is in development by the Zooniverse team, based at Chicago’s Adler Planetarium, in collaboration with the WorldWide Telescope Ambassadors program at Harvard. The goal of the project is to restore hidden metadata to images in published astronomical articles, some more than 100 years old, making the images useful to researchers. In this paper, I investigate a possible role for high school students in the oldAstronomy project. Using two focus groups, one at Milton School and one at Cambridge Ringe and Latin School, I investigate which aspects of participating in oldAstronomy would be of most interest: connections to real data? to real scientists? connecting to other students worldwide? viewing interesting images? researching a topic related to images encountered? It was explained to the focus group students, before they were surveyed, that requirements for their participation in oldAstronomy will include: digesting a scientific paper; summarizing results; and writing a summary that is understandable to the general public or participating in a more creative final project. Results show that students are very interested in working with real data and in the beauty and meaning of images. However, the results also show that students are, perhaps surprisingly, not interested in collaborating and communicating with other students, either in-person (as group work), or online. In response to the feedback from these students’ negative responses to group work, instead of a group final paper, students could benefit in a similar way with a reproduction of the peer review process. Additionally from the feedback of students, there was interest in an alternative form of final assessment. The results of our study suggest that instead of a standard write up, students can create: a 3D model of their object; a website about it; or a WorldWide Telescope tour.
Candid5 pos vel

Cara Battersby

and 18 more

It has recently been proposed (Goodman et al. 2014) that long, skinny, infrared dark clouds may trace out the densest features of the Milky Way, which include spiral arms, and possible inter-arm tendrils. The features are so long and skinny that they are almost certainly caused and maintained by a global gravitational potential, so they are not likely to be self-gravitating molecular clouds. These “Bones of the Milky Way” could be used to help piece together the structure of the Galaxy, shedding light on age-old questions, such as the number of spiral arms in our Galaxy and their locations. We have searched for and identified a handful of candidate Bones: long, filamentary infrared-dark clouds found in position-velocity space where our current model of the Galaxy predicts spiral arms should lie. Utilizing archival data, we have confirmed the location of these Bone candidates in the Galactic mid-plane and within 5 km/s of a spiral arm. We propose to use the IRAM 30-m to create the first ever high-resolution CO map (1mm) of a candidate “Bone of the Milky Way,” simultaneously with a suite of dense gas tracers at 3mm with IRAM. Capitalizing on IRAM’s unique ability to map CO over large areas at high angular resolution while simultaneously obtaining kinematic information about the dense gas, we will provide the first measure of structure and kinematics toward these unique Galactic structures. Our total time request is XX hours to map XX sq. arcminutes at 1mm (¹³CO and C¹⁸O 2-1) and 3mm (HCO+, HCN 1-0, etc.) toward our most promising Northern-hemisphere candidate Bone, “BC1.”
Auth

Hope How-Huan Chen

and 2 more

ABSTRACT. ρ Ophiuchii is a group of five B-stars, embedded in a nearby molecular cloud: Ophiuchus, at a distance of ∼ 119 pc. A “bubble”-like structure is found in dust thermal emission around ρ Oph. The circular structure on the Hα map further indicates that this bubble is physically connected to the source at the center. The goal of this paper is to estimate the impact of feedback from these embedded B-stars on the molecular cloud, by comparing the energy associated with the material entrained in the bubble to the total turbulent energy of the cloud. In this paper, we combine data from the COMPLETE Survey, which includes ¹²CO (1-0) and ¹³CO (1-0) molecular line emission from FCRAO, an extinction map derived from 2MASS near-infrared data using the NICER algorithm, and far-infrared data from IRIS (60/100 μm) with data from the Herschel Science Archive (PACS 100/160 μm and SPIRE 250/350/500 μm). With the wealth of data tracing different components of the cloud, we try to determine the best strategy to derive physical properties and to estimate the energy budget in the shell and in the cloud. We also experiment with the hierarchical Bayesian-fitting technique introduced by in an effort to eliminate the bias in the derived column densities and/or temperatures induced by noise in the far-IR data. We find that the energy entrained in the bubble is ∼ 12 % of the total turbulent energy of the Ophiuchus molecular cloud. This fraction is similar to the number give for the Perseus molecular cloud, and it suggests the non-negligible role of B-stars in driving the turbulence in clouds. We expect that a complete survey of “bubbles” in the Ophiuchus cloud will reveal the importance of B-star winds in molecular clouds.
L1688

Hope How-Huan Chen

and 5 more