More Like this

1. The cold dust content of the nearby galaxies IC 5325, NGC 7496, NGC 7590, and NGC 7599

   https://doi.org/10.1093/mnras/stab1048  

   Singh, Swapnil; Ashby, M L; Vig, Sarita; Ghosh, S K; Jarrett, T; Crawford, T M; Malkan, Matthew A; Archipley, M; Vieira, J D (May 2021, Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT Star-forming galaxies are rich reservoirs of dust, both warm and cold. But the cold dust emission is faint alongside the relatively bright and ubiquitous warm dust emission. Recently, evidence for a very cold dust (VCD) component has also been revealed via millimetre/submillimetre (mm/sub-mm) photometry of some galaxies. This component, despite being the most massive of the three dust components in star-forming galaxies, is by virtue of its very low temperature, faint and hard to detect together with the relatively bright emission from warmer dust. Here, we analyse the dust content of a carefully selected sample of four galaxies detected by IRAS, WISE, and South Pole Telescope (SPT), whose spectral energy distributions (SEDs) were modelled to constrain their potential cold dust content. Low-frequency radio observations using the Giant Metrewave Radio Telescope (GMRT) were carried out to segregate cold dust emission from non-thermal emission in mm/sub-mm wavebands. We also carried out AstroSat/Ultraviolet Imaging Telescope (UVIT) observations for some galaxies to constrain their SED at shorter wavelengths so as to enforce energy balance for the SED modelling. We constructed their SEDs across a vast wavelength range (extending from UV to radio frequencies) by assembling global photometry from GALEX FUV + NUV, UVIT, Johnson BRI, 2MASS, WISE, IRAC, IRAS, AKARI, ISO PHOT, Planck HFI, SPT, and GMRT. The SEDs were modelled with cigale to estimate their basic properties, in particular to constrain the masses of their total and VCD components. Although the galaxies’ dust masses are dominated by warmer dust, there are hints of VCD in two of the targets, NGC 7496 and NGC 7590. 

   more » « less
2. Neutral atomic and molecular gas dynamics in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496

   https://doi.org/10.1051/0004-6361/202450265  

   Laudage, Sebastian; Eibensteiner, Cosima; Bigiel, Frank; Leroy, Adam K; Meidt, Sharon; Schinnerer, Eva; de_Blok, W_J G; Querejeta, Miguele; Stuber, Sophia; Colombo, Dario; et al (October 2024, Astronomy & Astrophysics)

   Neutral atomic gas (H I) effectively traces galactic dynamics across mid to large galactocentric radii. However, its limitations in observing small-scale changes within the central few kiloparsecs, coupled with the often observed H Ideficit in galactic centers, necessitates the use of molecular gas emission as a preferred tracer in these regions. Understanding the dynamics of both neutral atomic and molecular gas is crucial for a more complete understanding of how galaxies evolve, funnel gas from the outer disk into their central parts, and eventually form stars. In this work we aim to quantify the dynamics of both, the neutral atomic and molecular gas, in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496 using new MeerKAT H Iobservations together with ALMA CO (2-1) observations from the PHANGS collaboration. We use the analysis tool^3DBarolo to fit tilted ring models to the H Iand CO observations. A combined approach of using the H Ito constrain the true disk orientation parameters before applying these to the CO datasets is tested. This paper sets expectations for the results of the upcoming high-resolution H Icoverage of many galaxies in the PHANGS-ALMA sample using MeerKAT or VLA, to establish a robust methodology for characterizing galaxy orientations and deriving dynamics from combing new H Iwith existing CO data. 

   more » « less
3. The V-band Variability of NGC 4151

   https://doi.org/10.3847/2515-5172/adbbf0  

   Lahue, Veronica; Bentz, Misty C; Padrick, Nolan (March 2025, Research Notes of the AAS)

   Abstract We presentV-band continuum light curves of the active galactic nucleus (AGN) in NGC 4151 created from a new photometric monitoring campaign with the Las Cumbres Observatory network. A total of 336 images were collected from 2023 December to 2024 June, with an average cadence of ∼2 images per day. Using aperture photometry and image subtraction, we constructed continuum light curves. Though both techniques generated similar light curves and demonstrated AGN variability on the scale of ΔV ≈ 0.4 mag, the galactic starlight contribution to the aperture photometry light curve produced a flux offset of ∼19% within a circular aperture of radius 31. The final light curves from this work will be compared against the variability of the broad emission lines to constrain the mass of the supermassive black hole and to model the broad-line region kinematics and geometry in NGC 4151. 

   more » « less
4. Fuelling the nuclear ring of NGC 1097

   https://doi.org/10.1093/mnras/stad1554  

   Sormani, Mattia_C; Barnes, Ashley_T; Sun, Jiayi; Stuber, Sophia_K; Schinnerer, Eva; Emsellem, Eric; Leroy, Adam_K; Glover, Simon_C_O; Henshaw, Jonathan_D; Meidt, Sharon_E; et al (May 2023, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT Galactic bars can drive cold gas inflows towards the centres of galaxies. The gas transport happens primarily through the so-called bar dust lanes, which connect the galactic disc at kpc scales to the nuclear rings at hundreds of pc scales much like two gigantic galactic rivers. Once in the ring, the gas can fuel star formation activity, galactic outflows, and central supermassive black holes. Measuring the mass inflow rates is therefore important to understanding the mass/energy budget and evolution of galactic nuclei. In this work, we use CO datacubes from the PHANGS-ALMA survey and a simple geometrical method to measure the bar-driven mass inflow rate on to the nuclear ring of the barred galaxy NGC 1097. The method assumes that the gas velocity in the bar lanes is parallel to the lanes in the frame co-rotating with the bar, and allows one to derive the inflow rates from sufficiently sensitive and resolved position–position–velocity diagrams if the bar pattern speed and galaxy orientations are known. We find an inflow rate of $$\dot{M}=(3.0 \pm 2.1)\, \rm M_\odot \, yr^{-1}$$ averaged over a time span of 40 Myr, which varies by a factor of a few over time-scales of ∼10 Myr. Most of the inflow appears to be consumed by star formation in the ring, which is currently occurring at a star formation rate (SFR) of $$\simeq\!1.8\!-\!2 \, \rm M_\odot \, yr^{-1}$$, suggesting that the inflow is causally controlling the SFR in the ring as a function of time. 

   more » « less
5. Modelling the baryon cycle in low-mass galaxy encounters: the case of NGC 4490 and NGC 4485

   https://doi.org/10.1093/mnras/sty2052  

   Pearson, Sarah; Privon, George C; Besla, Gurtina; Putman, Mary E; Martínez-Delgado, David; Johnston, Kathryn V; Gabany, R Jay; Patton, David R; Kallivayalil, Nitya (July 2018, Monthly Notices of the Royal Astronomical Society)