arXiv subjects

Anastasia Ponomareva

Publications and source records attributed to Anastasia Ponomareva.

4 recordsLinked to original sources

arXiv2026

Cosmology with Tully-Fisher HI Galaxy Surveys

The SKA Observatory will enable measurements of the Tully-Fisher relation for statistical samples of HI selected galaxies out to unprecedented depths and redshifts thanks to its unique combined spatial and spectral sensitivity. This chapter explores the transformative potential of such surveys for cosmology, in particular in the field of peculiar velocity measurements. We briefly review the present observational landscape for Tully-Fisher HI galaxy surveys and existing peculiar velocity datasets, and compare them with predictions for SKAO Tully-Fisher HI galaxy surveys with AA* and AA4 configurations of the SKA-Mid array. We discuss the extended range of cosmology science cases covered and enabled by such surveys.

astro-ph.CO↗

arXiv2026

Unlocking the Full Potential of SKAO Extra-galactic Science with High-multiplex Optical Spectroscopy

Parallel to the transformation in radio continuum and H I observations from SKAO pathfinders and precursors over the past decade has been the development of a new generation of multi-object spectrographs that will be equally transformational in a broad range of scientific areas. For all extragalactic radio source populations, this spectroscopy is essential for providing precise redshifts, separating star-formation and AGN activity, identifying accretion modes and revealing detailed host galaxy properties. It is only with the detailed emission line and optical continuum diagnostics from spectroscopy that we can begin to link the AGN and star-formation activity revealed by the radio continuum to the kinematic and chemical histories of galaxies. Crucially, extensive spectroscopy also unlocks the full potential of H I observations by enabling statistical measures of the H I content of galaxies out to $z = 1$ and beyond, through spectral stacking analyses, as well as comprehensively tracing the local environment and large-scale structure to enable studies of environmental effects on the baryon cycle. We outline the scientific synergies enabled by combining SKAO continuum and H I surveys with current optical spectroscopic surveys, as well as identifying the needs and scientific potential of future spectroscopic surveys dedicated to the radio source population with both existing and planned optical facilities.

astro-ph.GA↗

arXiv2026

Kinematically cold and warm planetary nebulae samples, HII regions and supernovae remnants in the disc of the face-on spiral galaxy NGC 628 (M74) -- The Planetary Nebulae Spectrograph with the H$α$ arm

We present the results for the galaxy NGC 628 observed with the Planetary Nebulae Spectrograph (PN.S) equipped with the H$α$ arm. With the third PN.S arm, the H$α$ arm, we measure the H$α$ fluxes, in addition to fluxes and line-of-sight velocities (LOSV) of monochromatic spatially unresolved [OIII] 5007Å sources. The narrow band color ([OIII] 5007Å-H$α$) vs m5007 magnitude diagram separates planetary nebulae (PNe) from single compact ionized HII regions and supernovae remnants (SNRs), which also emit in [OIII]5007 Å. The goals are to detect bona-fide PNe in the face-on spiral galaxy NGC 628 (M74) so that we can measure the velocity dispersion of the stars perpendicular to the main plane of the disc. This study validates the empirical selection criteria for PNe with the PN.S in star forming discs. We classified 442 PNe and 251 spatially isolated, unresolved HII regions: the PN.S with the H$α$ arm increased the number of known PNe by a factor 4. We find evidence for two kinematically distinct PN populations in the NGC 628 disc. The kinematically cold PN population dominates the PN luminosity function close to the bright cut-off magnitude, indicating that the PN massive, short-lived progenitors dominate the PNLF bright cut-off in NGC 628. The warmer PN component increasingly dominates at fainter magnitudes. The velocity dispersion orthogonal to the disc plane are σz,cold = 8.8 kms-1 and σz,warm =26.1 kms-1 respectively, over a range of radii 80 to 425 arcsec. These components contribute with the ratio 46% (cold) and 54% (warm). Once the velocity dispersion of the old component is matched with the population's scale height, the decomposition of the rotation curve for NGC 628 leads to a maximal disc, with the rotation of the baryonic component accounting for 78% of the total rotational velocity in NGC 628.

astro-ph.GA↗

arXiv2026

MIGHTEE HI observations of low surface brightness and ultra-diffuse galaxies in the XMM-LSS field

Untargeted neutral hydrogen (HI) surveys are well suited to identifying low surface brightness galaxies (LSBGs) that are gas rich, and they offer a complementary view to optically selected populations. We examined the LSBG population as identified via stellar and gaseous content using the MIGHTEE HI XMM-LSS early science data and the publicly available catalogs of optically identified LSBGs. There is currently little overlap between these datasets, with only three galaxies commonly detected. We performed surface brightness photometry of selected MIGHTEE HI detections to find 29 LSBGs, and 26 of these meet the size requirement (R_eff > 1.5 kpc) to be ultra-diffuse galaxies (UDGs). Furthermore, we extracted HI spectra at the location of all optically identified galaxies, placing upper limits on the HI-to-stellar mass ratio in these systems. While the HI-identified population overall tends toward bluer colors, the HI-identified and the optically selected samples mostly overlap in mean effective surface brightness, effective radii, and color. Although it is not straightforward to discern why the HI-identified LSBGs were missed in optical searches, this work highlights the utility of HI surveys in finding these faint systems. The HI-identified LSBGs are gas rich compared to the general HI-selected population. Furthermore, three out of four HI-selected UDGs with available kinematics show no systematic offset from the baryonic Tully-Fisher relation, although we are biased away from sources with low rotational velocities due to the low spectral resolution of the data. This work demonstrates the utility of HI observations for finding and characterizing the low surface brightness Universe.

astro-ph.GA↗