arXiv subjects

M. Yttergren

Publications and source records attributed to M. Yttergren.

3 recordsLinked to original sources

arXiv2026

Detailed lens modeling and kinematics of the submillimeter galaxy G09v1.97. An analysis of CO, H2O, H2O+, and dust continuum emission

The formation mechanisms of intensely starbursting galaxies at high redshift remain unknown. One possible mechanism for triggering these starbursts is mergers and interactions, but detecting these at high redshift remains a challenge. Observations of high-redshift gravitationally lensed galaxies enable studies of the interstellar medium and environment of these extreme starbursts in detail. We used high angular resolution observations of dust continuum, CO(6-5), H2O(211-202), and H2O+(202-111) emission to constrain the ongoing processes in the z = 3.63 gravitationally lensed submillimeter galaxy H-ATLAS J083051.0+013224 (G09v1.97). We used PyAutoLens to create a de-magnified source plane CO(6-5) emission line cube and performed kinematic modeling using 3DBarolo. Additionally, we investigated the properties of the continuum and molecular line emission in the source plane. We find that the regions of CO(6-5) and H2O(211-202) emission match closely in the source plane but that the dust continuum emission is more compact. We find that our lens modeling results do not require more than one source, contrary to what has been found in previous studies. Instead, we find that G09v1.97 resembles a rotating disk with Vmax/sigma = 2.8 +/- 0.4 with evidence for residual emission indicative of non-circular motions such as outflows, tidal tails, or an additional background galaxy. We suggest that the origin of the non-circular motions may be associated with a bi-conical outflow, a tidal tail from an interaction, or indicate the possible presence of an additional galaxy. We calculate the dynamical mass, gas mass, star-formation rate, and depletion time for G09v1.97 and find a high star-formation rate and low gas depletion time. In combination, this suggests that G09v1.97 has recently undergone an interaction, triggering intense star formation, and is in the process of settling into a disk.

astro-ph.GA↗

arXiv2025

Kinematics of synthetically observed high-$z$ rotating disks: reliability and biases of 3D fitting tools

Resolved high-redshift galaxy gas kinematics is a rapidly evolving field driven by increasingly powerful instrumentation. However, the resolution and sensitivity still impose constraints on interpretation. We investigate the uncertainties inherent to high-$z$ galaxy kinematical analysis by modelling a suite of rotating disk galaxies, generating synthetic interferometric ALMA observations, and fitting them with the 3D-kinematical tools 3DBarolo, GalPaK3D, and Qubefit. We present the recovered 3D-fitted kinematical parameters to assess their reliability, quantify the range of values possible for individual source studies, and establish the systematic biases present for observed samples. The $V/\sigma_{\rm V}$ ratio, which indicates how dynamically cold a system is, is of particular importance and depends on the choice of 3D-fitting tool. On average, 3DBarolo and Qubefit slightly overestimates $V/\sigma_{\rm V}$ ($<1\sigma$) and GalPaK3D underestimates it ($<2\sigma$). Therefore, all three tools are reliable for kinematical studies of averages of high-redshift galaxy samples. The value range possible for individual sources is significant, however, even more so for samples of not purely rotation dominated sources. To determine whether an observed galaxy is rotation dominated enough to be fitted with a 3D-kinematical tool, $V/\sigma_{\rm V}$ can be extracted directly from the observed data cube, with some caveats. We recommend that the median offsets, value ranges, and tool-dependent biases presented in this paper are taken into account when interpreting 3D-fitted kinematics of observed high-redshift galaxies.

astro-ph.GA↗

arXiv2021

Gas and stellar dynamics in Stephan's Quintet: Mapping the kinematics in a closely interacting compact galaxy group

Stephan's Quintet (SQ) is a nearby compact galaxy group and a perfect laboratory for studying the process of galaxy evolution through galaxy harassment and interaction. By analysing the kinematics of SQ we aim to provide an increased understanding of the group, the history of the interactions, their cause and effect, and the details regarding the physical processes occurring as galaxies interact. We have studied the ionised gas and stellar kinematics using the Large Binocular Telescope, and the molecular gas kinematics via CO using the IRAM 30m. Large areas of the group have been mapped and analysed. We obtain a total ionised gas mass in the regions chosen for closer analysis of 20.1$\pm$0.2x10^10 Msun and a total H2 gas mass of 21$\pm$2x10^9 Msun in the observed area (spectra integrated over the velocity range of SQ), while the star-forming (SF) clouds show an impressive complexity, with gas congregations at multiple velocities throughout the group. We map the large-scale nuclear wind in NGC7319 and its decoupled gas and stellar disk. With our high resolution data we can, for the first time, reveal the Seyfert 1 nature of NGC7319 and fit the narrow-line and broad-line regions. While the 12CO(1-0) map shows significant emission in the area of NGC7319, the bridge, and the SF ridge, the 12CO(2-1) emission shows a prevalence to the SF ridge, an area south of the NGC7318 pair, and an extension towards NGC7317 - connecting NGC7317 to the centre of the group, indicating a previous interaction. NGC7317 may also be a prime candidate for studies of the process of galaxy harassment. Furthermore, we connect the kinematical structures in SQ to the history of the group and the ongoing interaction with NGC7318B. Through our extensive observations of SQ we trace the kinematics and evolution of the complex processes and structures occurring in this nearby interactive group. [Abstract abridged]

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