Astronomy & Astrophysics最新文献

{"title":"Extinction and AGN over host galaxy contrast effects on the optical spectroscopic classification of AGN⋆","authors":"L. Barquín-González, S. Mateos, F. J. Carrera, I. Ordovás-Pascual, A. Alonso-Herrero, A. Caccianiga, N. Cardiel, A. Corral, R. M. Domínguez, I. García-Bernete, G. Mountrichas, P. Severgnini","doi":"10.1051/0004-6361/202348948","DOIUrl":"https://doi.org/10.1051/0004-6361/202348948","url":null,"abstract":"The optical spectroscopic classification of active galactic nuclei (AGN) into type 1 and type 2 can be understood in the frame of the AGN unification models. However, it remains unclear which physical properties are driving the classification into intermediate sub-types (1.0, 1.2, 1.5, 1.8, 1.9). To shed light on this issue, we present an analysis of the effect of extinction and AGN and host galaxy luminosities on sub-type determination for a sample of 159 X-ray selected AGN with a complete and robust optical spectroscopic classification. The sample spans a rest-frame 2–10 keV X-ray luminosity range of 10<sup>42<sup/>–10<sup>46<sup/> erg s<sup>−1<sup/> and redshifts between 0.05 and 0.75. From the fitting of their ultraviolet-to-mid-infrared spectral energy distributions, we extracted the observed AGN over total AGN+galaxy contrast, optical/ultraviolet line-of-sight extinction, as well as host galaxy and AGN luminosities. The observed contrast exhibits a clear decline with sub-type, distinguishing two main groups: 1.0–5 and 1.8–2. This difference is partly driven by an increase in extinction following the same trend. Nevertheless, 50% of 1.9s and 2s lack sufficient extinction to explain the lack of detection of broad emission lines, unveiling the necessity of an additional effect. Our findings show that 1.8–2s preferentially live in host galaxies with higher luminosities while displaying similar intrinsic AGN luminosities to 1.0–5s. Consequently, the AGN to host galaxy luminosity ratio diminishes, hindering the detection of the emission of the broad emission lines, resulting in the 1.8–2 classification of those with insufficient extinction. Thus, the combination of increasing extinction and decreasing AGN over galaxy luminosity ratio, mainly driven by an increasing host galaxy luminosity, constitutes the main reasons behind the sub-type classification into 1.0–5 and 1.8–2.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141545973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining the physical properties of gas in high-z galaxies with far-infrared and submillimetre line ratios","authors":"A. Schimek, C. Cicone, S. Shen, D. Decataldo, P. Klaassen, L. Mayer","doi":"10.1051/0004-6361/202449903","DOIUrl":"https://doi.org/10.1051/0004-6361/202449903","url":null,"abstract":"Optical emission line diagnostics, which are a common tool for constraining the properties of the interstellar medium (ISM) of galaxies, become progressively inaccessible at higher redshifts for ground-based facilities. Far-infrared (FIR) emission lines, which are redshifted into atmospheric windows that are accessible for ground-based submillimetre facilities, could provide ISM diagnostics alternative to optical emission lines. We investigated FIR line ratios involving [CII] <i>λ<i/>158 μm, [OIII] <i>λ<i/>88 μm, [OIII] <i>λ<i/>52 μm, [NII] <i>λ<i/>122 μm, and [NIII] <i>λ<i/>57 μm using synthetic emission lines applied to a high-resolution (<i>m<i/><sub>gas<sub/> = 883.4 <i>M<i/><sub>⊙<sub/>) cosmological zoom-in simulation, including radiative transfer post-processing with the code KRAMSES-RT at <i>z<i/> = 6.5. We find that the [CII]/[NII]122 ratio is sensitive to the temperature and density of photodissociation regions. It might therefore be a useful tool for tracing the properties of this gas phase in galaxies. We also find that [NII]/[NIII] is a good tracer of the temperature and that [OIII]52/[OIII]88 is a good tracer of the gas density of HII regions. Emission line ratios containing the [OIII] <i>λ<i/>88 μm line are sensitive to high-velocity outflowing gas.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141545975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The “C”: The large Chameleon-Musca-Coalsack cloud","authors":"Gordian Edenhofer, João Alves, Catherine Zucker, Laura Posch, Torsten A. Enßlin","doi":"10.1051/0004-6361/202450374","DOIUrl":"https://doi.org/10.1051/0004-6361/202450374","url":null,"abstract":"Recent advancements in 3D dust mapping have transformed our understanding of the Milky Way’s local interstellar medium, enabling us to explore its structure in three spatial dimensions for the first time. In this Letter, we use the most recent 3D dust map by Edenhofer et al. to study the well-known Chameleon, Musca, and Coalsack cloud complexes, located about 200 pc from the Sun. We find that these three complexes are not isolated but rather connect to form a surprisingly well-defined half-ring, constituting a single C-shaped cloud with a radius of about 50 pc, a thickness of about 45 pc, and a total mass of about 5 × 10<sup>4<sup/> <i>M<i/><sub>⊙<sub/>, or 9 × 10<sup>4<sup/> <i>M<i/><sub>⊙<sub/> if including everything in the vicinity of the C-shaped cloud. Despite the absence of an evident feedback source at its center, the dynamics of young stellar clusters associated with the C structure suggest that a single supernova explosion about 4 Myr–10 Myr ago likely shaped this structure. Our findings support a single origin story for these cloud complexes, suggesting that they were formed by feedback-driven gas compression, and offer new insights into the processes that govern the birth of star-forming clouds in feedback-dominated regions, such as the Scorpius-Centaurus association.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141546323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving mid-infrared thermal background subtraction with principal component analysis","authors":"H. Rousseau, S. Ertel, D. Defrère, V. Faramaz, K. Wagner","doi":"10.1051/0004-6361/202348574","DOIUrl":"https://doi.org/10.1051/0004-6361/202348574","url":null,"abstract":"<i>Context<i/>. Ground-based large-aperture telescopes, interferometers, and future extremely large telescopes equipped with adaptive optics (AO) systems provide angular resolution and high-contrast performance superior to space-based telescopes at thermal infrared wavelengths. Their sensitivity, however, is critically limited by the high thermal background inherent to ground-based observations in this wavelength regime.<i>Aims<i/>. We aim to improve the subtraction quality of the thermal infrared background from ground-based observations using principal component analysis (PCA).<i>Methods<i/>. We used data obtained with the Nulling-Optimized Mid-Infrared Camera on the Large Binocular Telescope Interferometer as a proxy for general high-sensitivity AO-assisted ground-based data. We applied both a classical background subtraction – using the mean of dedicated background observations – and a new background subtraction based on a PCA of the background observations. We compared the performances of these two methods in both high-contrast imaging and aperture photometry.<i>Results<i/>. Compared to the classical approach for background subtraction, PCA background subtraction delivers up to two times better contrasts down to the diffraction limit of the LBT’s primary aperture (i.e., 350 mas in <i>N<i/>-band), that is, in the case of high-contrast imaging. An improvement factor between two and three was obtained over the mean background retrieval within the diffraction limit in the case of aperture photometry.<i>Conclusions<i/>. The PCA background subtraction significantly improves the sensitivity of ground-based thermal infrared imaging observations. When apply to LBTI’s nulling interferometry data, we expect the method to improve the sensitivity by a similar factor of two to three. This study paves the way to maximizing the potential of future infrared ground-based instruments and facilities, such as the future 30m-class telescopes.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141545835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct detectability of tidally heated exomoons by photometric orbital modulation","authors":"E. Kleisioti, D. Dirkx, X. Tan, M. A. Kenworthy","doi":"10.1051/0004-6361/202449428","DOIUrl":"https://doi.org/10.1051/0004-6361/202449428","url":null,"abstract":"<i>Aims<i/>. We investigate whether volcanic exomoons can be detected in thermal wavelength light curves due to their phase variability along their orbit. The method we use is based on the photometric signal variability that volcanic features or hotspots would cause in infrared (IR) wavelengths, when they are inhomogeneously distributed on the surface of a tidally heated exomoon (THEM).<i>Methods<i/>. We simulated satellites of various sizes around an isolated planet and modeled the system’s variability in two IR wavelengths, taking into account photon shot noise. The moon’s periodic signal as it orbits the planet introduces a peak in the frequency space of the system’s time-variable flux. We investigated the THEM and system properties that would make a moon stand out in the frequency space of its host’s variable flux.<i>Results<i/>. The moon’s signal can produce a prominent feature in its host’s flux periodogram at shorter IR wavelengths for hotspots with temperatures similar to the ones seen on the Jovian moon, Io, while the same moon would not be identifiable in longer IR wavelengths. By comparing observations at two different wavelengths, we are able to disentangle the signal of an exomoon with transiting and non-transiting orbital inclinations from the planet’s signal in the frequency domain for system distances up to ~10 pc for Mars-sized exomoons and even further for Earth-sized ones.<i>Conclusions<i/>. This method enlarges the parameter space of detectable exomoons around isolated planetary mass objects and directly imaged exoplanets, as it is sensitive to Io- to Earth-sized exomoons with hot volcanic features for a wide range of non-transiting orbital inclinations. Exomoon transits and the detection of outgassed volcanic molecules can subsequently confirm a putative detection.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 3D view on the local gravitational instability of cold gas discs in star-forming galaxies at 0 ≲ z ≲ 5","authors":"C. Bacchini, C. Nipoti, G. Iorio, F. Roman-Oliveira, F. Rizzo, P. E. Mancera Piña, A. Marasco, A. Zanella, F. Lelli","doi":"10.1051/0004-6361/202449925","DOIUrl":"https://doi.org/10.1051/0004-6361/202449925","url":null,"abstract":"Local gravitational instability (LGI) is considered crucial for regulating star formation and gas turbulence in galaxy discs, especially at high redshift. Instability criteria usually assume infinitesimally thin discs or rely on approximations to include the stabilising effect of the gas disc thickness. We test a new 3D instability criterion for rotating gas discs that are vertically stratified in an external potential. This criterion reads <i>Q<i/><sub>3D<sub/> < 1, where <i>Q<i/><sub>3D<sub/> is the 3D analogue of the Toomre parameter <i>Q<i/>. The advantage of <i>Q<i/><sub>3D<sub/> is that it allows us to study LGI in and above the galaxy midplane in a rigorous and self-consistent way. We apply the criterion to a sample of 44 star-forming galaxies at 0 ≲ <i>z<i/> ≲ 5 hosting rotating discs of cold gas. The sample is representative of galaxies on the main sequence at <i>z<i/> ≈ 0 and includes massive star-forming and starburst galaxies at 1 ≲ <i>z<i/> ≲ 5. For each galaxy, we first apply the Toomre criterion for infinitesimally thin discs, finding ten unstable systems. We then obtain maps of <i>Q<i/><sub>3D<sub/> from a 3D model of the gas disc derived in the combined potential of dark matter, stars and the gas itself. According to the 3D criterion, two galaxies with <i>Q<i/> < 1 show no evidence of instability and the unstable regions that are 20% smaller than those where <i>Q<i/> < 1. No unstable disc is found at 0 ≲ <i>z<i/> ≲ 1, while ≈60% of the systems at 2 ≲ <i>z<i/> ≲ 5 are locally unstable. In these latter, a relatively small fraction of the total gas (≈30%) is potentially affected by the instability. Our results disfavour LGI as the main regulator of star formation and turbulence in moderately star-forming galaxies in the present-day Universe. LGI likely becomes important at high redshift, but the input by other mechanisms seems required in a significant portion of the disc. We also estimate the expected mass of clumps in the unstable regions, offering testable predictions for observations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"White dwarf magnetospheres: Shielding volatile content of icy objects and implications for volatile pollution scarcity","authors":"Wen-Han Zhou, Shang-Fei Liu, Douglas N. C. Lin","doi":"10.1051/0004-6361/202449271","DOIUrl":"https://doi.org/10.1051/0004-6361/202449271","url":null,"abstract":"<i>Context<i/>. About 25–50% of white dwarfs are found to be contaminated by heavy elements, which are believed to originate from external sources such as planetary materials. Elemental abundances suggest that most of the pollutants are rocky objects and only a small fraction of white dwarfs bear traces of volatile accretion.<i>Aims<i/>. In order to account for the scarcity of volatile pollution, we investigate the role of the white dwarfs’ magnetospheres in shielding the volatile content of icy objects.<i>Methods<i/>. We estimated the volatile sublimation of inward drifting exocomets. We assume the orbits of the exocomets are circularized by the Alfvén wing drag that is effective for long-period comets.<i>Results<i/>. Volatile material can sublimate outside the corotation radius and be shielded by the magnetic field. The two conditions for this volatile-shielded mechanism are that the magnetosphere radius must be larger than the corotation radius and that the volatiles are depleted outside the corotation radius, which requires a sufficiently slow orbital circularization process. We applied our model to nine white dwarfs with known rotational periods, magnetic fields, and atmosphere compositions. Our volatile-shielded model may explain the excess of volatile elements such as C and S in the disk relative to the white dwarf atmosphere in WD2326+049 (G29-38). Nevertheless, given the sensitivity of our model to the circularization process and material properties of icy objects, there remains considerable uncertainty in our results.<i>Conclusions<i/>. We emphasize the importance of white dwarfs’ magnetic fields in preventing the accretion of volatile gas onto them. Our work suggests a possible explanation for the scarcity of volatile-accretion signatures among white dwarfs. We also identify a correlation between the magnetic field strength, the spin period, and the composition of pollutants in white dwarf atmospheres. However, given the uncertainties in our model, more observations are necessary to establish more precise constraints on the relevant parameters.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transitions in magnetic behavior at the substellar boundary","authors":"E. Magaudda, B. Stelzer, R. A. Osten, J. S. Pineda, St. Raetz, M. McKay","doi":"10.1051/0004-6361/202449403","DOIUrl":"https://doi.org/10.1051/0004-6361/202449403","url":null,"abstract":"We aim to advance our understanding of magnetic activity and the underlying dynamo mechanism at the end of the main sequence. To this end, we have embarked on collecting simultaneous X-ray and radio observations for a sample of M7..L0 dwarfs in the solar neighborhood using <i>XMM-Newton<i/> jointly with the <i>Jansky<i/> Very Large Array (JVLA) and the Australia Telescope Compact Array (ATCA). We supplemented the data from these dedicated campaigns with X-ray data from the all-sky surveys of the ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Russian Spektrum-Roentgen-Gamma mission (SRG). Moreover, we complement this multiwavelength data set with rotation periods that we measured from light curves acquired with the Transiting Exoplanet Survey Satellite (TESS). We limited the sample to objects with rotation period of < 1 day, focusing on the study of a transition in magnetic behavior suggested by a drastic change in the radio detection rate at <i>υ<i/> sin <i>i<i/> ≈ 38 km s<sup>−1<sup/>, corresponding to <i>P<i/><sub>rot<sub/> ≈ 0.2 day for a typical ultracool dwarf (UCD) radius of <i>R<i/><sub>★<sub/> = 0.15 <i>R<i/><sub>⊙<sub/>. Finally, to enlarge the target list, we have compiled archival X-ray and radio data for UCDs from the literature, and we have analyzed the abovementioned ancillary eROSITA and TESS observations for these objects’ analogous to the targets from our dedicated X-ray/radio campaigns. We compiled the most up to date radio/X-ray luminosity (<i>L<i/><sub>R,ν<sub/> − <i>L<i/><sub>x<sub/>) relation for 26 UCDs with rotation periods (<i>P<i/><sub>rot<sub/>) lower than 1 day, finding that rapid rotators lie the furthest away from the “Güdel-Benz” relation previously studied for earlier-type stars. Radio bursts are mainly (although not exclusively) experienced by very fast UCDs (<i>P<i/><sub>rot<sub/> ≤ 0.2 day), while X-ray flares are seen by objects spanning the whole range of rotation. Finally, we examined the <i>L<i/><sub>x<sub/>/<i>L<i/><sub>bol<sub/> versus <i>P<i/><sub>rot<sub/> relation, where our sample of UCDs spans a large activity level range, that is log(<i>L<i/><sub>x<sub/>/<i>L<i/><sub>bol<sub/>) = −5.5 to log(<i>L<i/><sub>x<sub/>/<i>L<i/><sub>bol<sub/>) = −3. Although they are all fast rotating, X-ray activity evidently decouples from that of normal dynamos. In fact, we found no evident relation between the X-ray emission and rotation, reinforcing previous speculations on a bimodal dynamo across late-type dwarfs. One radio-detected object, 2MJ0838, has a rotation period consistent with the range of auroral bursting sources; while it displays moderately circularly polarized emission, there is no temporal variation in the polarized flux. A radio flare from this object is interpreted as gyrosynchrotron emission, and it displays X-ray and optical flares. Among the ten UCDs observed with the dedicated X-ray/radio campaigns, we found a slowly rotating apparent auroral emitter (2MJ0752) that is also o","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Runaway BN supergiant star HD 93840: Progenitor of an imminent core-collapse supernova above the Galactic plane","authors":"D. Weßmayer, M. A. Urbaneja, K. Butler, N. Przybilla","doi":"10.1051/0004-6361/202347732","DOIUrl":"https://doi.org/10.1051/0004-6361/202347732","url":null,"abstract":"We present a quantitative spectral analysis of the extreme nitrogen-enhanced supergiant HD 93840 (BN1 Ib) at an intermediate galactic latitude. Based on an optical high-resolution spectrum and complementary ultraviolet and infrared (spectro-)photometry, in addition to <i>Gaia<i/> data, we carried out a full characterisation of the star’s properties. We used both hydrostatic and unified (photosphere+wind) model atmospheres that account for deviations from local thermodynamic equilibrium. A highly unusual surface CNO-mixing signature and a marked stellar overluminosity compared to the mass imply a binary channel for the star’s past evolution. The kinematics shows that it has reached its current position above the Galactic plane as a runaway star, likely ejected by the supernova explosion of its former companion star. Its current bulk composition, with a notably increased mean molecular weight due to core He- and progressed shell H-burning, suggests an advanced evolutionary stage. It is poised to yield a rare core-collapse supernova of a blue supergiant about ten OB star population scale heights above the Galactic disk relatively soon, contributing to the metal enrichment of the circumgalactic medium.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Search and analysis of giant radio galaxies with associated nuclei (SAGAN)","authors":"Shishir Sankhyayan, Pratik Dabhade","doi":"10.1051/0004-6361/202450011","DOIUrl":"https://doi.org/10.1051/0004-6361/202450011","url":null,"abstract":"We investigated the prevalence of giant radio galaxies (GRGs), some of the largest structures powered by supermassive black holes, within supercluster environments, and the influence of such environments on their properties. Utilising two large catalogues of superclusters (401) and GRGs (1446), we established the existence of 77 GRGs (5.3%) residing in 64 superclusters (16%) within 0.05 ≤ <i>z<i/> ≤ 0.42. Among the 77 GRGs found in superclusters, we identified ∼70% as residing within galaxy clusters. Within the subset of GRGs not located in superclusters, which constitutes 94.7% of the sample, a mere 21% are associated with galaxy clusters, while the remaining majority are situated in sparser environments. We examined the influence of differing environments, such as cluster versus non-cluster and supercluster versus non-supercluster regions, on the size of GRGs, while also exploring the driving factors behind their overall growth. Our findings show that the largest GRGs (≳3 Mpc) grow in underdense environments beyond the confines of dense environments. Moreover, we show that ∼24% of 1446 GRGs reside in galaxy clusters. We conclude that GRGs preferentially grow in sparser regions of the cosmic web and have a significantly larger median size. Finally, we demonstrate the potential of GRGs as astrophysical probes with specific cases where GRGs, exhibiting polarised emissions and located behind superclusters (acting as natural Faraday screens), were used to estimate magnetic field strengths of the supercluster environment at sub-microgauss levels.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":6.5,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}