Show threadPᵉtɘr Wᵉil8acherOct 30, 2024
Interesting how the center of the galaxy is still compatible with the star-forming main sequence but the global molecular gas mass is orders of magnitude too low!
#gLSB #Malin1
Pᵉtɘr Wᵉil8acherOct 30, 2024
Another new paper, led by Gaspar Galaz and colleagues in Chile (https://arxiv.org/abs/2410.22230). We detect molecular gas in the giant low-surface brightness galaxy Malin 1 for the first time with #ALMA. The detection in the center (see image) is clear and at least one further detection in the northern disk seems likely.
#gLSB #Malin1
First Detection of Molecular Gas in the Giant Low Surface Brightness Galaxy Malin 1

After over three decades of unsuccessful attempts, we report the first detection of molecular gas emission in Malin 1, the largest spiral galaxy observed to date, and one of the most iconic giant low surface brightness galaxies. Using ALMA, we detect significant $^{12}$CO(J=1-0) emission in the galaxy's central region and tentatively identify CO emission across three regions on the disc. These observations allow for a better estimate of the H$_2$ mass and molecular gas mass surface density, both of which are remarkably low given the galaxy's scale. By integrating data on its HI mass, we derive a very low molecular-to-atomic gas mass ratio. Overall, our results highlight the minimal presence of molecular gas in Malin 1, contrasting sharply with its extensive, homogeneous atomic gas reservoir. For the first time, we position Malin 1 on the Kennicutt-Schmidt (K-S) diagram, where it falls below the main sequence for normal spirals, consistent with previous upper limits but now with more accurate figures. These findings are crucial for constraining our understanding of star formation processes in environments characterized by extremely low molecular gas densities and for refining models of galaxy formation, thereby improving predictions concerning the formation, evolution, and distribution of these giant, elusive galaxies.

arXiv.org
Show threadPᵉtɘr Wᵉil8acherApr 17, 2024
This (Johnston et al., https://arxiv.org/abs/2404.04099) is already the 2nd paper on the partial MUSE data of #Malin1 (following Junais et al., https://www.aanda.org/articles/aa/full_html/2024/01/aa47669-23/aa47669-23.html).
Fingers crossed that we'll finally get the remaining 3/4 now that we have shown how useful it is.
#musevlt
A MUSE View of the Core of the Giant Low Surface Brightness Galaxy Malin 1

Aims. The central region of the Giant Low Surface Brightness galaxy Malin 1 has long been known to have a complex morphology with evidence of a bulge, disc, and potentially a bar hosting asymmetric star formation. In this work, we use VLT/MUSE data to resolve the central region of Malin 1 in order to determine its structure. Methods. We use careful light profile fitting in every image slice of the datacube to create wavelength-dependent models of each morphological component, from which we could cleanly extract their spectra. We then used the kinematics and emission line properties from these spectra to better understand the nature of each component extracted from our model fit. Results. We report the detection of a pair of distinct sources at the centre of this galaxy with a separation of ~1.05", which corresponds to a separation on sky of ~1.9 kpc. The radial velocity data of each object confirms that they both lie in the kinematic core of the galaxy, and analysis of the emission lines reveals that the central compact source is more consistent with being ionized by star formation and/or a LINER, while the off-centre compact source lies closer to the separation between star-forming galaxies and AGN. Conclusions. This evidence suggests that the centre of Malin 1 hosts either a bar with asymmetric star formation or two distinct components in which the off-centre compact source could either be a star-forming clump containing one or more star clusters that is in the process of falling into the core of the galaxy and which will eventually merge with the central NSC, or a clump of gas infalling into the centre of the galaxy from either outside or from the disc and triggering star formation there.

arXiv.org
Show threadPᵉtɘr Wᵉil8acherApr 17, 2024
The off-center source seems to be ionized mostly by star-formation (with a bit of shocks?), forming ~25x more stars than the nucleus. It could be a young star cluster to soon merge with the main nucleus.
#Malin1 #musevlt
Pᵉtɘr Wᵉil8acherApr 17, 2024
Evelyn Johnston led the paper on the discovery of an "off-center compact source" in the giant LSB galaxy Malin 1 based on the existing MUSE data, now accepted at A&A.
https://arxiv.org/abs/2404.04099
#musevlt #Malin1 #LSBgalaxy
A MUSE View of the Core of the Giant Low Surface Brightness Galaxy Malin 1

Aims. The central region of the Giant Low Surface Brightness galaxy Malin 1 has long been known to have a complex morphology with evidence of a bulge, disc, and potentially a bar hosting asymmetric star formation. In this work, we use VLT/MUSE data to resolve the central region of Malin 1 in order to determine its structure. Methods. We use careful light profile fitting in every image slice of the datacube to create wavelength-dependent models of each morphological component, from which we could cleanly extract their spectra. We then used the kinematics and emission line properties from these spectra to better understand the nature of each component extracted from our model fit. Results. We report the detection of a pair of distinct sources at the centre of this galaxy with a separation of ~1.05", which corresponds to a separation on sky of ~1.9 kpc. The radial velocity data of each object confirms that they both lie in the kinematic core of the galaxy, and analysis of the emission lines reveals that the central compact source is more consistent with being ionized by star formation and/or a LINER, while the off-centre compact source lies closer to the separation between star-forming galaxies and AGN. Conclusions. This evidence suggests that the centre of Malin 1 hosts either a bar with asymmetric star formation or two distinct components in which the off-centre compact source could either be a star-forming clump containing one or more star clusters that is in the process of falling into the core of the galaxy and which will eventually merge with the central NSC, or a clump of gas infalling into the centre of the galaxy from either outside or from the disc and triggering star formation there.

arXiv.org