Autor: Dey, Subhrata - Prolib Integro

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Tytuł:: Panchromatyczne modelowanie rozkładu energii widmowej jasnych galaktyk podczerwonych
Panchromatic spectral energy distribution modeling of infared bright galaxies
Autorzy:: Dey, Subhrata
Współwytwórcy:: Ostrowski, Michał
Goyal, Arti
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Tytuł:: Radio-only and radio-to-far-ultraviolet spectral energy distribution modeling of 14 ULIRGs : insights into the global properties of infrared bright galaxies
Autorzy:: Goyal, Arti
Małek, Katarzyna
Dey, Subhrata
Díaz-Santos, Tanio
Opis:: We present detailed spectral energy distribution (SED) modeling of 14 local ultraluminous infrared galaxies (ULIRGs) with outstanding photometric data from the literature covering the ultraviolet–infrared (FIR) and radio bands (∼50 MHz to ∼30 GHz). We employ the CIGALE SED fitting code to model the ultraviolet–FIR–radio SED. For the radio-only SED modeling, we use the UltraNest package, leveraging its nested sampling algorithm. Combining the results from our previous study on 11 luminous infrared galaxies (LIRGs), we discuss the global astrophysical properties of a sample of 25 starburst galaxies (z < 0.5). Their radio spectra are frequently characterized by bends and turnovers, with no indication of ULIRGs exhibiting more complicated SEDs than LIRGs despite showing more signs of interactions. Including radio measurements in the CIGALE modeling constrained the dust luminosity and star formation rate (SFR) estimates by more than 1 order of magnitude better than previously reported for starburst galaxies. We show that total and nonthermal radio luminosity at 1.4 and 4.8 GHz frequencies can be good estimators of recent SFRs for all LIRGs and those ULIRGS with an insignificant influence of active galactic nuclei. A weaker but still significant correlation is observed between radio SFRs at 1.4 GHz and old (averaged over 100 Myr) SFRs based on SED modeling, indicative of multiple episodes of starburst activity during their lifetime. The thermal radio luminosity at 4.8 GHz is a better tracer of recent star formation than the thermal luminosity at 1.4 GHz. Statistically, our modeled nonthermal radio spectral indices do not significantly correlate with redshift, stellar mass, SFR, specific SFR, and dust mass.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Tytuł:: Low-frequency radio continuum imaging and SED modeling of 11 LIRGs : radio-only and FUV to radio bands
Autorzy:: Seymour, Nicholas
Charmandaris, Vassilis
Goyal, Arti
Galvin, Timothy J.
Dey, Subhrata
Santos, Tanio Díaz
Małek, Katarzyna
Piotrowska, Julia
Opis:: We present a detailed analysis of 11 local luminous infrared galaxies from ultraviolet through far-infrared to radio (∼70 MHz to ∼15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observations at 325 and 610 MHz from the GMRT and the measurements from public archives. Our main results are (1) radio SEDs show turnovers and bends, (2) the synchrotron spectral index of the fitted radio spectra ranges between −0.5 and −1.7, and (3) the infrared luminosity, dust mass, dust temperature, stellar mass, star formation rates (SFRs), and active galactic nuclei (AGN) fraction obtained from CIGALE fall within the range exhibited by galaxies of the same class. The ratio of 60 μm infrared and 1.4 GHz radio luminosity, the 1.4 GHz thermal fraction, and emission measure range between 2.1 and 2.9, 0.1% and 10%, 0.02 and 269.5 $\times$ 10$^{6}$ cm$^{-6}$ pc, respectively. We conclude that the turnovers seen in the radio SEDs are due to free–free absorption; this is supported by the low AGN fraction derived from the CIGALE analysis. The decomposed 1.4 GHz thermal and nonthermal radio luminosities allowed us to compute the SFR using scaling relations. A positive correlation is observed between the SFR$_{IR}$ obtained 10 Myr ago (compared to 100 Myr ago) and 1.4 GHz radio (total and nonthermal) because similar synchrotron lifetimes are expected for typical magnetic field strengths observed in these galaxies (≈50 μG).
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Tytuł:: Spatially resolved spectrophotometric SED modeling of NGC 253s central molecular zone : I. Star formation in extragalactic giant molecular clouds
Autorzy:: Schoenell, William
Cid Fernandes, Roberto
Kanaan, Antonio
Tanaka, Kunihiko
Fernández-Ontiveros, Juan A.
Meier, David S.
Song, Yiqing
Hamed, Mahmoud
Ronconi, Tommaso
Colzi, Laura
Małek, Katarzyna
Ribeiro, Tiago
Sasse, Victor H.
Rivilla, Víctor M.
Demarco, Ricardo
Muller, Sebastien
Nakanishi, Kouichiro
Mangum, JeffreyG.
Harada, Nanase
Panda, Swayamtrupta
Donevski, Darko
Henkel, Christian
Yan, Yaoting
Yoshimura, Yuki
Krabbe, Ângela C.
Mendes de Oliveira, Claudia
Dey, Subhrata
Lopes, Amanda R.
Martín, Sergio
Humire, Pedro K.
Sakamoto, Kazushi
Goyal, Arti
Opis:: Context. Studying the interstellar medium in nearby starbursts is essential for gaining insights into the physical mechanisms driving these extreme objects, which are thought to be analogs of young, primeval, star-forming galaxies. This task is now feasible due to deep spectro-photometric data enabled by rapid advancements in ground- and space-based facilities. To fully leverage this wealth of information, extracting insights from the spectral line properties and the spectral energy distribution (SED) is imperative. Aims. This study aims to produce and analyze the physical properties of the first spatially resolved multiwavelength SED of an extragalactic source that covers six decades in frequency (from near-ultraviolet, NUV, to centimeter, cm, wavelengths) at an angular resolution of 3″, which corresponds to a linear scale of ∼51 pc at the distance of NGC 253. We focus on the central molecular zone (CMZ) of this starburst galaxy, which contains giant molecular clouds (GMCs) responsible for half of the galaxy’s star formation. Methods. We retrieved archival data from near-UV to centimeter wavelengths, covering six decades of spectral range. We computed the SEDs to fit the observations, using the GalaPy code and confronting the results with the CIGALE code for validation. We also employed the STARLIGHT code to analyze the stellar optical spectra of the GMCs. Results. Our results reveal significant differences between internal and external GMCs in terms of stellar and dust masses, star formation rates (SFRs), and bolometric luminosities, among others, with internal GMCs doubling maximum values of the external ones in most of the cases. We obtained tight relations between monochromatic stellar tracers and star-forming conditions obtained from panchromatic emission. We find that the best SFR tracers are radio continuum bands at 33 GHz, radio recombination lines (RRLs), and the total infrared (IR) luminosity range (L$_{IR}$; 8–1000 μm) as well as the IR emission at 60 μm. The emission line diagnostics based on the BPT and WHAN diagrams suggest that the nuclear region of NGC 253 exhibits shock signatures, placing it in the composite zone typically associated with hybrids of active galactic nucleus (AGN) hosting and star-forming regions, while the AGN fraction from panchromatic emission is negligible (≤7.5%). Conclusions. Our findings demonstrate the significant heterogeneity within the CMZ of NGC 253, with central GMCs exhibiting high densities, elevated SFRs, and greater dust masses compared to their external counterparts. We confirm the effectiveness of certain centimeter photometric bands as a reliable method to estimate the global SFR, in accordance with previous studies – this time on GMC scales.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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