Galaxy Zoo Bar Lengths: large-scale bar length and width measurements for 8,230 galaxies imaged in multiple surveys by the Hubble Space Telescope

This repository contains the catalogue of bar lengths and widths for 8,230 galaxy images included in Galaxy Zoo Bar Lengths (https://www.zooniverse.org/projects/vrooje/galaxy-zoo-bar-lengths). The data table is included as a CSV, a FITS table, and a VO Table. There is also a zip file containing the subject images. 

The columns in hutchinsonsmith2026_gzbl_table2_fulltable_withurls.* are as follows:

subject_id -- Zooniverse (Panoptes) subject ID, a unique value across all Zooniverse projects

OBJID_prev_GZ -- ID from previous Galaxy Zoo project (If numeric: image is from GZ Hubble, Willett et al. 2017. If mixed numbers/characters: image is from GZ CANDELS, Simmons et al. 2017)

RA -- Right Ascension (J2000)  [deg]

Dec -- Declination (J2000)  [deg]

scale_arcsec_per_pixel -- conversion factor between GZBL subject image pixels and arcseconds (see paper for details on how GZBL images are zoomed relative to the original GZH/GZC project images)

n_class_total -- total number of classifications submitted for this subject

t0_has_bar_count -- number of votes collected in task t0 (question task; should match n_class_total, as everyone answers the first question)

t0_has_bar_yes_frac -- fraction of votes to task t0 for answer: yes

t0_has_bar_no_frac -- fraction of votes to task t0 for answer: no

t1_spiral_arms_attached_count -- number of votes collected in task t1 (question task)

t1_spiral_arms_attached_yes_frac -- fraction of votes in task t1 for answer: yes

t1_spiral_arms_attached_no_frac -- fraction of votes in task t1 for answer: no

t1_spiral_arms_attached_no_spiral_arms_frac -- fraction of votes in task t1 for answer: no spiral arms

t2_ring_attached_count -- number of votes collected in task t2 (question task)

t2_ring_attached_yes_frac -- fraction of votes in task t2 for answer: yes

t2_ring_attached_no_frac -- fraction of votes in task t2 for answer: no

t2_ring_attached_no_ring_frac -- fraction of votes in task t2 for answer: no ring

t3_bar_length_class_count -- number of votes collected in task t3 (drawing task)

n_lines_highprob -- number of aggregated line clusters containing marks from at least 30% of classifiers (if there is only a length cluster and a width cluster, this will be 2)

length_p_true_positive -- fraction of classifiers who drew a line in the "length" cluster, out of all classifiers who marked the subject in t3 (estimate of reliability of measurement)

length_x1 -- x coordinate of 1st (leftmost, i.e. x1 < x2 is enforced) point defining the aggregated length line  [pix]

length_y1 -- y coordinate of 1st point defining the aggregated length line  [pix]

length_x2 -- x coordinate of 2nd (rightmost) point defining the aggregated length line  [pix]

length_y2 -- y coordinate of 2nd point defining the aggregated length line  [pix]

angle_length -- angle of length mark (CCW/x) (-atan((length_y2length_y1)/(length_x2length_x1)))  [deg]

length_line_dist_pix -- length line measurement in GZBL pixels (not necessarily native instrument pixels)  [pix]

width_p_true_positive -- fraction of classifiers who drew a line in the "width" cluster, out of all classifiers who marked the subject in t3 (estimate of reliability of measurement)

width_x1 -- x coordinate of 1st (leftmost, i.e. x1 < x2 is enforced) point defining the aggregated width line  [pix]

width_y1 -- y coordinate of 1st point defining the aggregated width line  [pix]

width_x2 -- x coordinate of 2nd (rightmost) point defining the aggregated width line  [pix]

width_y2 -- y coordinate of 2nd point defining the aggregated width line  [pix]

angle_width -- angle of width mark (CCW/x) (-atan((width_y2width_y1)/(width_x2width_x1)))  [deg]

width_line_dist_pix -- width line measurement in GZBL pixels (not necessarily native instrument pixels, see paper for details)  [pix]

angle_length_width -- angle between length and width line  [deg]

bar_length_arcsec -- bar length measurement  [arcsec]

bar_width_arcsec -- bar width measurement  [arcsec]

i_gal -- disk inclination along line of sight (see paper for more details on axis ratio b/a used) (acos(ba_gal_use))  [deg]

delta_bar -- angle between bar length and disk major axis (angle_lengththeta_gal_use) where theta_gal_use is described further in the paper  [deg]

psi_gal -- angle between bar width and disk major axis (angle_widththeta_gal_use) where theta_gal_use is described further in the paper  [deg]

length_deproject_factor -- correction factor for inclination for bar LENGTH (any units, multiply by observed length) (sqrt(pow(cos(delta_bar),2) + pow(sin(delta_bar),2)/pow(cos(phi_gal),2)))

width_deproject_factor -- correction factor for inclination for bar WIDTH (any units, multiply by observed width) (sqrt(pow(cos(psi_bar),2) + pow(sin(psi_bar),2)/pow(cos(phi_gal),2)))

subject_image_standard -- URL for GZBL subject image, standard colors

subject_image_inverted -- URL for GZBL subject image, inverted colors

While the URLs are included for completeness, we also include a zipfile containing both standard and inverted images of all subjects. The filenames of the images can be reconstructed using the OBJID_prev_GZ column as [OBJID_prev_GZ]_standard.jpg for standard color images and likewise with _inverted.jpg for the inverted images.

Contact Tenley Hutchinson-Smith or Brooke Simmons if you have questions about the usage of this catalogue.