MWP1BUBBLE - Milky Way Project First Data Release IR Bubble Catalog

Overview

This table contains a new catalog of 5106 infrared bubbles created through visual classification via the online citizen science website 'The Milky Way Project' (MWP). Bubbles in the new catalog have been independently measured by at least five individuals, producing consensus parameters for their positions, radii, thicknesses, eccentricities and position angles. Citizen scientists - volunteers recruited online and taking part in this research - have independently rediscovered the locations of at least 86% of three widely used catalogs of bubbles and H II regions while finding an order of magnitude more objects. 29% of the bubbles in the Milky Way Project catalog lie on the rim of a larger bubble, or have smaller bubbles located within them, opening up the possibility of better statistical studies of triggered star formation. This online resource of the Milky Way Project provides a crowd-sourced map of bubbles and arcs in the Milky Way, and will enable better statistical analysis of Galactic star formation sites. This table is the first data release of the MWP IR Bubble Catalog: the authors anticipate a future release of a second, refined catalog incorporating better data-reduction techniques.

Catalog Bibcode

2012MNRAS.424.2442S

References

The Milky Way Project First Data Release: A Bubblier Galactic Disc

     Simpson R.J., Povich M.S., Kendrew S., Lintott C.J., Bressert E.,
     Arvidsson K., Cyganowski C., Maddison S., Schawinski K., Sherman R.,
     Smith A.M., Wolf-Chase G.
     <Mon. Not. Royal Astr. Soc. 424, 2442-2460 (2012)>
     =2012MNRAS.424.2442S      (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in March 2013 based on the CDS Catalog J/MNRAS/424/2442 files mwplarge.dat and mwpsmall.dat.

Parameters

Bubble_Type
This HEASARC-created parameter indicates whether the object is a 'large' bubble and listed in Table 2 of the reference paper or a 'small' bubble and listed in Table 3 of the reference paper. Notice that the definition of these two types is an operational one and not necessarily related to their physical sizes, as discussed in Section 3.4 of the reference paper.

Name
The name of the bubble ('MWP1 GLLL.lll+BB.bbb' for large bubbles, 'MWP1 GLLL.ll+BB.bbS' for small bubbles), using the MWP1 prefix (for Milky Way Project, 1st data release) and the Galactic coordinates of the source (and the suffix 'S' for small bubbles). This was created by the HEASARC using a modified form of that given in the the reference paper in order to better conform withe the position-based IAU style recommended by the Dictionary of Nomenclature of Celestial Objects. For both bubble types, the HEASARC has added a space between the 'MWP1' prefix and the rest of the name. In addition, for large bubbles, the HEASARC removed the 4th decimal place in the Galactic Latitude while, for small bubbles, the HEASARC removed the 3rd decimal place in the Galactic Longitude and the 3rd and 4th decimal places in the Galactic Latitude since they were always zeroes. One consequence of the truncation of the large bubble names is that there are two duplicate name pairs, 'MWP1 G305.168+00.162' (originally named 'MWP1G305.168+00.1626' and 'MWP1G305.168+00.1628') and 'MWP1 G341.206-00.230' (originally named 'MWP1G341.206-00.2302' and 'MWP1G341.206-00.2303').

Alt_Names
Where cross-correlation is possible, alternative identifiers from Churchwell et al. (2006, ApJ, 649, 759) and Churchwell et al. (2007, ApJ, 670, 428) are given for the bubble.

RA
The Right Ascension of the bubble in the selected equinox. The bubble's position was given in Galactic coordinates to a precision of 0.001 degrees in each coordinate (for large bubbles) or to a precision of 0.01 degrees in each coordinate (for small bubbles) in the original reference.

Dec
The Declination of the bubble in the selected equinox. The bubble's position was given in Galactic coordinates to a precision of 0.001 degrees in each coordinate (for large bubbles) or to a precision of 0.01 degrees in each coordinate (for small bubbles) in the original reference.

LII
The Galactic Longitude of the bubble, given to a precision of 0.001 degrees (for large bubbles) or to a precision of 0.01 degrees (for small bubbles) in the original reference.

BII
The Galactic Latitude of the bubble, given to a precision of 0.001 degrees (for large bubbles) or to a precision of 0.01 degrees (for small bubbles) in the original reference.

Effective_Radius
The effective radius of the bubble, in arcminutes. For large bubbles, this is calculated from the geometric means of the inner and outer diameters in both axes of the ellipse characterizing the bubble, defined as R_eff = 0.5 * [(R_in*r_in)^0.5 + (R_out*r_out)^0.5], where R_in, R_out are the inner and outer ellipse semi-major axes, and r_in, r_out are the inner and outer ellipse semi-minor axes, respectively. The minimum effective radius imposed by the limitations of the MWP drawing tool (see Section 3.4 of the reference paper) is 0.27 arcminutes. For small bubbles listed in Table 3 of the reference paper, this parameter is described as the 'mean radius' and the method by which it was calculated is not explicitly described.

Effective_Thickness
The effective thickness of the bubble, in arcminutes. For large bubbles, this is calculated from the geometric means of the inner and outer diameters in both axes of the ellipse characterizing the bubble, defined as T_eff = (R_out*r_out)^0.5 - (R_in*r_in)^0.5, where R_in, R_out are the inner and outer ellipse semi-major axes, and r_in, r_out are the inner and outer ellipse semi-minor axes, respectively. This parameter is not listed for small bubbles.

Eccentricity
The eccentricity of the inner ellipse characterizing the bubble. This is calculated using [(R_in)² - (r_in)²]/R_in, where R_in, r_in are the inner ellipse semi-major and semi-minor axes, respectively. Note that the MWP drawing tools do not allow for different eccentricities in the inner and outer sizes of the bubbles. This parameter is not listed for small bubbles.

Position_Angle
The position angle of the major axis of the ellipse characterizing the bubble, in degrees, measured from the vertical of the Y axis (the HEASARC suspects that this may be the direction of North Galactic Latitude). This parameter is not listed for small bubbles.

Hit_Rate
The 'hit rate' of the bubble. This is the ratio of the number of qualifying bubbles drawn to the number of times the bubble was seen by users on the MWP website. A clean bubble produced from a cluster of five user drawings placed on to an asset that was seen 50 times would have a hit rate of 0.1, for example. In cases where a bubble could be marked in more than one asset, for example across different zoom levels, the total view counts are summed, such that a cluster of five bubbles drawn on to two assets of 50 views each would have a hit rate of 0.05. The hit rate thus gives a measure of consensus among users that a bubble is present in the data.

Position_Dispersion
The dispersion in the position of the bubble, in arcminutes. The bubble's dispersion is calculated as the spread in the coordinates of the individual classifications [(sigma_b)² + (sigma_l)²], where the sigma parameters are the variances in the Galactic coordinate values. This parameter is not listed for small bubbles.

Hierarchy_Flags
The hierarchy flags for the bubble, where '1' denotes bubbles identified as having smaller bubbles on their rim and '2' bubbles located within a larger bubble.

Contact Person

Questions regarding the MWP1BUBBLE database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:31:21 EDT