J/A+A/708/A125 Star forming clump properties (Moretti+, 2026)
Molecular gas and star formation in GASP jellyfish galaxies.
Moretti A., Paladino R., Bacchini C., Marasco A., Giunchi E.,
Poggianti B.M., Hunt L.K., Deb T., Vulcani B., Gullieuszik M., Lassen A.,
Wolter A., Gitti M., Radovich M., Fritz J., Tomicic N.
<Astron. Astrophys. 708, A125 (2026)>
=2026A&A...708A.125M 2026A&A...708A.125M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Radio sources ; Star Forming Region ;
Millimetric/submm sources
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: star formation
Abstract:
Several studies have reported a nearly linear correlation between the
molecular gas and star formation rate surface density, the so-called
Kennicutt-Schmidt (KS) law.
We aim to retrieve the KS relation for a sample of four star-forming
galaxies located in nearby clusters, disturbed by the effects of the
ram pressure stripping, as testing this law in galaxies subject to
different environmental conditions can provide key information on the
physics of star formation.
To perform our analysis, we used ALMA band 6 and band 3 data coupled
with MUSE data at spatial resolution of ∼1 kpc. Moreover, we
analyzed data of star-forming complexes detected through their
Hα ionized gas emission. We also derived the star formation
efficiencies of the star-forming regions nested in these big complexes
using the star formation rates derived from spatially resolved HST
images and various recipes for the corresponding cold gas phase.
We find that ram-pressure-stripped galaxies show normal-to-low star
formation efficiencies, depending on the position within the galaxy
and on the local gas density: the inner dense regions in the disk show
higher efficiencies with respect to the outer regions, including the
gaseous tails. The global relation between the star formation rate
density and the molecular gas surface density is superlinear, likely
suggesting the shortening of the depletion times at high gas mass
densities caused by the ram pressure. Within the star-forming
complexes, the star formation efficiency is very similar to the one
observed at 1kpc scale in undisturbed star-forming disks.
Interestingly, this result holds also for the star-forming complexes
located in the stripped gas tails. The analysis of HST resolved clumps
suggests that the molecular gas is not uniformly distributed within
the star-forming complexes, but its density distribution follows a
steeper profile.
Description:
This file lists the properties of the star forming clumps in the disks
and in the tails of four jellyfish galaxies belonging to the GASP
sample that possess both ionized gas emission from MUSE and a CO(2-1)
emission detected with ALMA. The cold molecular gas emission is
derived by extracting the flux from a circular region with the same
size of the MUSE ionized gas emitting region. The H2 mass has been
determined by using the standard Milky Way conversion factor and a
line ratio of 0.65.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 87 314 Star forming clump properties
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- BlobId Object Identifier
11- 19 F9.5 deg RAdeg Right Ascension (J2000)
21- 29 F9.5 deg DEdeg Declination (J2000)
31- 35 F5.2 kpc+2 Area Blob area measured by MUSE
37- 44 F8.2 km/s V21 Velocity
46- 51 F6.2 km/s sigma21 Velocity dispersion
53- 58 F6.2 Jy Flux21G CO(2-1) gaussian flux
60- 64 F5.2 Jy Flux21 CO(2-1) total flux
66- 69 F4.2 Jy e_Flux21 Error on flux
71- 74 F4.1 --- S/N21 Signal-to-Noise ratio
76 A1 --- VisFlag [03] Visual classification flag (1)
78- 82 F5.2 Jy Flux21fin Final flux value
84- 87 F4.2 10+9Msun MH2fin Final H2 masses
--------------------------------------------------------------------------------
Note (1): Visual classification flag as follows:
0 = When the Gaussian fit did not reproduce signal in the wings of the
line, we preferred to use the integral of the positive flux within
±3σHα as a proxy for the total amount of gas to be
associated with the Hα emission, irrespective of the Gaussian
fit
3 = in most cases a single Gaussian fit was able to describe the CO line
emission arising from the star-forming knots in JO201, JO204, and
JO206, while in JW100 we often found multiple peaks in the observed
spectra (see e.g., Fig. 8), implying the presence of separated
components along the line of sight simply superimposed in the
integrated sky region. When possible we therefore attributed to the
star-forming region the Gaussian fit of the component that was
coincident also with the Hα emission a flag 3
--------------------------------------------------------------------------------
Acknowledgements:
Alessia Moretti, alessia.moretti(at)inaf.it
(End) Patricia Vannier [CDS] 20-Feb-2026