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## MWP1BUBBLE - Milky Way Project First Data Release IR Bubble Catalog |
HEASARC Archive |

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)

**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.