J/MNRAS/542/52 3D velocities of YSO-MC associations (Zhou+, 2025)
Kinematics of the interstellar medium using Gaia: A catalogue of 102 young
stellar object-molecular cloud associations within 3.5 kpc of the Sun with 3D
velocities.
Zhou J.-X., Li G.-X., Chen B.-Q.
<Mon. Not. R. Astron. Soc. 542, 52 (2025)>
=2025MNRAS.542...52Z 2025MNRAS.542...52Z (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; YSOs ; Molecular clouds
Keywords: galaxies: ISM - ISM: structure - ISM: clouds - stars: formation -
ISM: kinematics dynamics
Abstract:
Kinematic information is crucial for understanding the evolution of
complex systems, such as interstellar gas. Obtaining full 3D kinematic
information is a crucial final step for modeling and interpretation.
Molecular clouds are nurseries where stars are born. Stars at a very
early stage, like young stellar objects (YSOs), inherit the spatial
and kinematic structure of the gas patches they originate from. In
this paper, we combine measurements of radial velocities towards the
gas and the kinematic information of YSOs from Gaia DR3 to derive 3D
velocities of a sample of YSO (Young Stellar Object)-MC (Molecular
Cloud) complexes at d≲3.5kpc from the Sun. We find that the
molecular interstellar medium traced by the YSO-MC complexes generally
follows Galactic rotation, with an additional peculiar velocity of
8.6km/s. The random motion of these complexes in the Galactic XY plane
is more energetic than motion along the Z direction. A catalogue
containing the 3D velocities of the YSO-MC complexes at different
reference frames is available, and the distances and 3D velocities of
well-known molecular clouds are presented. Our results set the
foundation for exploring the interplay between the Galaxy, the
molecular ISM, and star formation.
Description:
Using a sample of 15149 YSOs younger than 3Myr, we extract 150
associations with sizes ranging from several pc to one hundred pc and
study their velocity structures. This allows us to probe the
velocities of the gas that these YSOs are associated with.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 271 102 Parameters of YSO associations
clouds.dat 264 7 Cloud velocities
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Id [0/101] Sequential number
5- 12 F8.3 deg GLON [] Galactic longitude
14- 20 F7.3 deg GLAT Galactic latitude
22- 26 F5.3 kpc Dist Heliocentric distance
28- 32 F5.3 kpc e_Dist Uncertainty in heliocentric distance
34- 39 F6.2 mas/yr pmGLON Proper motion in Galactic longitude
41- 46 F6.2 mas/yr pmGLAT Proper motion in Galactic latitude
48- 51 F4.2 mas/yr e_pmGLON Uncertainty in proper motion in GLON
53- 56 F4.2 mas/yr e_pmGLAT Uncertainty in proper motion in GLAT
58- 63 F6.2 km/s HRV Heliocentric radial velocity
65- 69 F5.2 km/s e_HRV Uncertainty in heliocentric radial velocity
71- 77 F7.3 kpc Xg Galactocentric X position (toward GC)
79- 84 F6.3 kpc Yg Galactocentric Y position
(in rotation direction)
86- 91 F6.3 kpc Zg Galactocentric Z position
(toward Galactic north)
93- 98 F6.2 km/s VX Velocity along X in Galactic rectangular
coordinates
100-105 F6.2 km/s VY Velocity along Y in Galactic rectangular
coordinates
107-112 F6.2 km/s VZ Velocity along Z in Galactic rectangular
coordinates
114-118 F5.2 km/s e_VX Uncertainty in VX
120-124 F5.2 km/s e_VY Uncertainty in VY
126-129 F4.2 km/s e_VZ Uncertainty in VZ
131-136 F6.2 km/s Vrg Galactocentric radial velocity
138-144 F7.2 km/s Vtg Galactocentric tangential velocity in plane
146-150 F5.2 km/s Vzg Galactocentric vertical velocity
152-156 F5.2 km/s e_Vrg Uncertainty in Vrg
158-162 F5.2 km/s e_Vtg Uncertainty in Vtg
164-167 F4.2 km/s e_Vzg Uncertainty in Vzg
169-174 F6.2 km/s VrgPec Peculiar radial velocity (Galactocentric)
176-181 F6.2 km/s VtgPec Peculiar tangential velocity
(Galactocentric)
183-187 F5.2 km/s VzgPec Peculiar vertical velocity (Galactocentric)
189-194 F6.2 km/s Vxga Galactocentric velocity in X
196-201 F6.2 km/s Vyga Galactocentric velocity in Y
203-207 F5.2 km/s Vzga Galactocentric velocity in Z
209-213 F5.2 km/s e_Vxga Uncertainty in Vxga
215-219 F5.2 km/s e_Vyga Uncertainty in Vyga
221-224 F4.2 km/s e_Vzga Uncertainty in Vzga
226-231 F6.2 km/s Vx-de-ro Residual Vxga after subtracting rotation
233-238 F6.2 km/s Vy-de-ro Residual Vyga after subtracting rotation
240-244 F5.2 km/s Vz-de-ro Residual Vzga after subtracting rotation
246-251 F6.2 km/s VxPec peculiar velocity in X
253-258 F6.2 km/s VyPec peculiar velocity in Y
260-264 F5.2 km/s Vsigma2D 2D velocity dispersion
266-271 F6.2 pc Size Size of the YSO association
--------------------------------------------------------------------------------
Byte-by-byte Description of file: clouds.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Cloud Cloud name
17- 24 F8.3 deg GLON [] Galactic longitude
26- 32 F7.3 deg GLAT Galactic latitude
34- 38 F5.3 kpc Dist Heliocentric distance
40- 44 F5.3 kpc e_Dist Uncertainty in heliocentric distance
46- 51 F6.2 mas/yr pmGLON Proper motion in Galactic longitude
53- 58 F6.2 mas/yr pmGLAT Proper motion in Galactic latitude
60- 63 F4.2 mas/yr e_pmGLON Uncertainty in proper motion in GLON
65- 68 F4.2 mas/yr e_pmGLAT Uncertainty in proper motion in GLAT
70- 74 F5.2 km/s HRV Heliocentric radial velocity
76- 79 F4.2 km/s e_HRV Uncertainty in heliocentric radial velocity
81- 86 F6.3 kpc Xg Galactocentric X position (toward GC)
88- 93 F6.3 kpc Yg Galactocentric Y position
(in rotation direction)
95-100 F6.3 kpc Zg Galactocentric Z position
(toward Galactic north)
102-107 F6.2 km/s VX Velocity along X in Galactic rectangular
coordinates
109-114 F6.2 km/s VY Velocity along Y in Galactic rectangular
coordinates
116-120 F5.2 km/s VZ Velocity along Z in Galactic rectangular
coordinates
122-125 F4.2 km/s e_VX Uncertainty in VX
127-130 F4.2 km/s e_VY Uncertainty in VY
132-135 F4.2 km/s e_VZ Uncertainty in VZ
137-141 F5.2 km/s Vrg Galactocentric radial velocity
143-149 F7.2 km/s Vtg Galactocentric tangential velocity in plane
151-155 F5.2 km/s Vzg Galactocentric vertical velocity
157-160 F4.2 km/s e_Vrg Uncertainty in Vrg
162-165 F4.2 km/s e_Vtg Uncertainty in Vtg
167-170 F4.2 km/s e_Vzg Uncertainty in Vzg
172-176 F5.2 km/s VrgPec Peculiar radial velocity (Galactocentric)
178-182 F5.2 km/s VtgPec Peculiar tangential velocity
(Galactocentric)
184-188 F5.2 km/s VzgPec Peculiar vertical velocity (Galactocentric)
190-195 F6.2 km/s Vxga Galactocentric velocity in X
197-201 F5.2 km/s Vyga Galactocentric velocity in Y
203-207 F5.2 km/s Vzga Galactocentric velocity in Z
209-212 F4.2 km/s e_Vxga Uncertainty in Vxga
214-217 F4.2 km/s e_Vyga Uncertainty in Vyga
219-222 F4.2 km/s e_Vzga Uncertainty in Vzga
224-228 F5.2 km/s Vx-de-ro Residual Vxga after subtracting rotation
230-235 F6.2 km/s Vy-de-ro Residual Vyga after subtracting rotation
237-241 F5.2 km/s Vz-de-ro Residual Vzga after subtracting rotation
243-247 F5.2 km/s VxPec peculiar velocity in X
249-253 F5.2 km/s VyPec peculiar velocity in Y
255-258 F4.2 km/s Vsigma2D 2D velocity dispersion
260-264 F5.2 pc Size Size of the YSO association
--------------------------------------------------------------------------------
Acknowledgements:
Ji-Xuan Zhou, jizhuaa(at)gmail.com
(End) Patricia Vannier [CDS] 22-Jul-2025