J/AJ/170/185 SHEDR3: All-sky molecular clouds extinction catalog (Zhang+, 2025)
CU-JADE: A method for traversing extinction jumps along the line of sight.
Zhang S., Su Y., Chen X., Fang M., Du F., Zhang S., Yan Q.-Z., Liu X.,
Zhang M., Sun Y., Yang Ji
<Astron. J., 170, 185 (2025)>
=2025AJ....170..185Z 2025AJ....170..185Z
ADC_Keywords: Molecular clouds; Extinction; Galactic plane; Optical; Masers;
Interstellar medium; Radio sources; Photometry; Carbon monoxide
Keywords: Interstellar medium ; Interstellar extinction ; Distance measure ;
Molecular clouds
Abstract:
Although interstellar dust extinction serves as a powerful distance
estimator, the solar system's location within the Galactic plane
complicates distance determinations, especially for molecular clouds
(MCs) at varying distances along the line of sight (LoS). The presence
of complex extinction patterns along the LoS introduces degeneracies,
resulting in less accurate distance measurements to overlapping MCs in
crowded regions of the Galactic plane. In this study, we develop the
CUSUM-based Jump-point Analysis for Distance Estimation (CU-JADE), a
novel method designed to help mitigate these observational challenges.
The key strengths of CU-JADE include: (1) sensitivity to detect abrupt
jumps in Distance-Aλ (D-A) data sets, (2) minimal systematic
errors as demonstrated on both mock and observed data, and (3) the
ability to combine CUSUM analysis with multiwavelength data to improve
the completeness of distance measurements for nearby gas structures,
even for extinction values as low as ΔAV≥0.15mag. By combining
CO survey data with a large sample of stars characterized by
high-precision parallaxes and extinctions, we uncovered the
multilayered molecular gas distribution in the high-latitude Cepheus
region. We also determined accurate distances to MCs beyond the Cygnus
Rift by analyzing the intricate structure of gas and extinction within
the Galactic plane. Additionally, we constructed a full-sky 3D
extinction map extending to 4kpc, which provides critical insights
into dense interstellar medium components dominated by molecular
hydrogen. These results advance our understanding of the spatial
distribution and physical properties of MCs across the Milky Way.
Description:
We utilize various CO surveys to trace the distribution of molecular
gas. The CO data in the Galactic plane originates from the Milky Way
Imaging Scroll Painting (MWISP project, Su+2019, 2019ApJS..240....9S 2019ApJS..240....9S).
The spatial resolution of the observational data is ∼50", and the
spectral resolution is ∼0.2km/s. The typical rms noise level is
∼0.5K for 12CO and ∼0.3K for 13CO and C18O. In this work, we
focus on molecular clouds (MCs) located in a specific region of the
Galactic plane toward the Cygnus region (i.e., 72°≤l≤87°,
|b|≤5.1°; Zhang+2024, J/AJ/167/220).
The 1.2m Center for Astrophysics (CfA) telescope survey
(Dame+2001, 2001ApJ...547..792D 2001ApJ...547..792D) incorporates data from 37 individual
12CO (J=1-0) line surveys covering most of the Galactic plane. With an
angular resolution of 8.6', the surveys provide exceptional data and
improved sensitivity and compared to the MWISP survey. We utilized the
CfA data set to systematically investigate dust-gas correlations in
the Cepheus region, particularly focusing on the relationship between
CO structures and the corresponding extinction features in
100°≤l≤120° and 0°≤b≤20°.
We use stellar parameters (e.g., extinction) and parallaxes from
different star samples to measure distances of extinction structures.
In this work, we generate 3D extinction maps using different stellar
catalogs. For the Cygnus region near the Galactic plane, we retrieved
the same stellar sample from Gaia DR3 (I/355) and performed a comparative
analysis in line with previous results (Zhang+2024, J/AJ/167/220).
StarHorse EDR3 (SHEDR3; Anders+2022, I/354) released a catalog
featuring 362 million star samples. These stars, whose parameters are
derived from the data of Gaia EDR3 (I/350), have been cross-matched
with the photometric catalogs of Pan-STARRS1 (II/389), SkyMapper (II/379),
2MASS (II/246), and AllWISE (II/328). We take all stars in SHEDR3
sample with relative distance uncertainties smaller than 0.2.
We adopted the comprehensive stellar catalog (hereafter ZGR23)
published by Zhang+2023 (2023MNRAS.524.1855Z 2023MNRAS.524.1855Z), which provides
astrophysical parameters for 220 million stars that was trained on a
carefully curated subset of high-resolution stellar spectra from the
Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST;
DR11, V/162). The construction process also integrated multiwavelength
data sets, including Gaia BP/RP low-resolution spectra (R∼30-100;
I/355), 2MASS near-infrared photometry (J, H, Ks bands; II/246), and
unWISE mid-infrared photometry (W1, W2 bands; II/363). We selected a
refined sample of 123,284,327 stars.
To verify the accuracy of our method, we need MCs with precise
distance measurements. Distances derived from observations of masers
using Very Long Baseline Interferometry (Xu+2006, 2006Sci...311...54X 2006Sci...311...54X;
Reid+2014, J/ApJ/783/130) are considered to be among the most reliable
measurements available. We use 75 maser samples from
Reid+2019 (J/ApJ/885/131) and Hyland+2023 (J/ApJ/953/21). Finally, we
utilize young open clusters (YOCs; Hunt+2023, J/A+A/673/A114) as
tracers of star-forming regions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 69 152564 The all-sky extinction catalog derived from SHEDR3
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See also:
II/196 : Vilnius Photometry in two Nebulae (Straizys et al., 1993)
II/363 : The band-merged unWISE Catalog (Schlafly+, 2019)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/379 : SkyMapper Southern Sky Survey. DR4 (Onken+, 2024)
II/389 : The Pan-STARRS release 1 (PS1) Survey - DR2 (Magnier+, 2025)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/354 : StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)
V/162 : LAMOST DR11 catalogs (Luo+, 2026)
J/ApJS/110/21 : Molecular clouds in Cepheus and Cassiopeia (Yonekura+ 1997)
J/ApJ/783/130 : Parallaxes of high mass star forming regions (Reid+, 2014)
J/ApJ/786/29 : Catalog of distances to molecular clouds (Schlafly+, 2014)
J/MNRAS/484/1838 : Spatial substructure of Cygnus OB2 (Berlanas+, 2019)
J/A+A/625/A135 : Gal. interstellar dust Gaia-2MASS 3D maps (Lallement+, 2019)
J/ApJ/885/131 : ∼200 high-mass SFR plx & pm with VLBI (Reid+, 2019)
J/A+A/643/A36 : HI-to-H2 transit. in local diffuse ISM dataset (Bellomi+, 2020)
J/MNRAS/493/351 : A large catalogue of molecular clouds (Chen+, 2020)
J/A+A/639/A26 : Cold HI, H2 & total H column dens. FITS maps (Kalberla+, 2020)
J/MNRAS/502/6080 : New members of Cygnus OB2 from Gaia DR2 (Orellana+, 2021)
J/MNRAS/504/2968 : The Alma catalogue of OB stars - II. (Pantaleoni+, 2021)
J/MNRAS/508/2370 : Revisiting the Cygnus OB associations (Quintana+, 2021)
J/ApJ/911/55 : FUSE survey of H2 in the Galactic disk (Shull+, 2021)
J/MNRAS/505/5164 : The Gaia view of the Cepheus flare (Szilagyi+, 2021)
J/ApJS/257/51 : Morphological classif. of MWISP 12CO mol. clouds (Yuan+, 2021)
J/ApJS/262/5 : A CO survey of the entire northern sky (Dame+, 2022)
J/MNRAS/511/2302 : Molecular clouds study from 3D extinction maps (Guo+, 2022)
J/A+A/664/A174 : Galactic interstellar dust Gaia-2MASS 3D maps (Vergely+, 2022)
J/A+A/673/A114 : Improving the open cluster census. II. (Hunt+, 2023)
J/ApJ/953/21 : Inverse MultiView. II. 6.7GHz methanol masers (Hyland+, 2023)
J/A+A/684/A162 : Starlight-polarization-based tomography (Pelgrims+, 2024)
J/A+A/682/A161 : H2 in the diffuse ISM (Skalidis+, 2024)
J/AJ/168/203 : Dust clouds masses, color excesses and distances (Sun+, 2024)
J/AJ/167/220 : 207 molecular clouds distance measurements; MWISP (Zhang+, 2024)
J/A+A/694/A97 : Magnetic field of the Radcliffe Wave (Panopoulou+, 2025)
J/AJ/170/24 : Properties of new members in stellar group ASCC 127 (Wang+, 2025)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 deg GLON Galactic longitude of extinction component
across the sky
7- 11 F5.1 deg GLAT Galactic latitude of extinction component
across the sky
13- 14 I2 --- Nlos [1/11] Number of Line of Sight (LoS)
extinctions (Comps) (1)
16- 20 F5.3 kpc Dist [0.16/4.96] Median distance (2)
22- 26 F5.3 kpc E_Dist [0.16/5.69] Upper 84% boundary in Dist (2)
28- 32 F5.3 kpc e_Dist [0.16/4.81] Lower 16% boundary in Dist (2)
34- 39 F6.3 mag Fore-AV [-5e-3/6.82] Mean extinction in the pre-jump
distance bin
41- 45 F5.3 mag Back-AV [0.14/8.24] Mean extinction in the post-jump
distance bin
47- 51 F5.3 mag e_Fore-AV [0.094/2.24] Standard deviation in Fore-AV
53- 57 F5.3 mag e_Back-AV [0.1/2.4] Standard deviation in Back-AV
59- 63 F5.3 mag Delta-AV [0.15/4.41] Magnitude of extinction jumps (3)
65- 69 I5 --- Nstar [184/43657] Number of stars
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Note (1): Identified by the CU-JADE method, including those with
Delta-AV<0.15mag.
Note (2): From bootstrap sampling.
Note (3): Identified by the CU-JADE method.
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Robin Leichtnam [CDS] 09-Jul-2026