The Astronomy and Astrophysics Review最新文献

{"title":"Cloud property trends in hot and ultra-hot giant gas planets (WASP-43b, WASP-103b, WASP-121b, HAT-P-7b, and WASP-18b)","authors":"Ch. Helling, D. Lewis, D. Samra, L. Carone, V. Graham, O. Herbort, K. Chubb, M. Min, R. Waters, V. Parmentier, N. Mayne","doi":"10.1051/0004-6361/202039911","DOIUrl":"https://doi.org/10.1051/0004-6361/202039911","url":null,"abstract":"Ultra-hot Jupiters are the hottest exoplanets discovered so far. Observations begin to provide insight into the composition of their extended atmospheres and their chemical day/night asymmetries. Both are strongly affected by cloud formation. We explore trends in cloud properties for a sample of five giant gas planets: WASP-43b, WASP-18b, HAT-P-7b, WASP-103b, and WASP-121b. This provides a reference frame for cloud properties for the JWST targets WASP-43b and WASP-121b. We further explore chemically inert tracers to observe geometrical asymmetries, and if the location of inner boundary of a 3D GCM matters for the clouds that form. The large day/night temperature differences of ultra-hot Jupiters cause large chemical asymmetries: cloud-free days but cloudy nights, atomic vs. molecular gases and respectively different mean molecular weights, deep thermal ionospheres vs. low-ionised atmospheres, undepleted vs enhanced C/O. WASP-18b, as the heaviest planet in the sample, has the lowest global C/O. The global climate may be considered as similar amongst ultra-hot Jupiters, but different to that of hot gas giants. The local weather, however, is individual for each planet since the local thermodynamic conditions, and hence the local cloud and gas properties, differ. The morning and the evening terminator of ultra-hot Jupiters will carry signatures of their strong chemical asymmetry such that ingress/egress asymmetries can be expected. An increased C/O ratio is a clear sign of cloud formation, making cloud modelling a necessity when utilizing C/O (or other mineral ratios) as tracer for planet formation. The changing geometrical extension of the atmosphere from the day to the nightside may be probed through chemically inert species like helium. Ultra-hot Jupiters are likely to develop deep atmospheric ionospheres which may impact the atmosphere dynamics through MHD processes.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"33 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82166690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Refining Saturn's deuterium-hydrogen ratio via IRTF/TEXES spectroscopy","authors":"J. Blake, L. Fletcher, T. Greathouse, G. Orton, H. Melin, M. Roman, A. Antuñano, P. Donnelly, N. Rowe-Gurney, O. King","doi":"10.1051/0004-6361/202038229","DOIUrl":"https://doi.org/10.1051/0004-6361/202038229","url":null,"abstract":"The abundance of deuterium in giant planet atmospheres provides constraints on the reservoirs of ices incorporated into these worlds during their formation and evolution. Motivated by discrepancies in the measured deuterium-hydrogen ratio (D/H) on Jupiter and Saturn, we present a new measurement of the D/H ratio in methane for Saturn from ground-based measurements. We analysed a spectral cube (covering 1151-1160 cm−1 from 6 February 2013) from the Texas Echelon Cross Echelle Spectrograph (TEXES) on NASA’s Infrared Telescope Facility (IRTF) where emission lines from both methane and deuterated methane are well resolved. Our estimate of the D/H ratio in stratospheric methane, 1.65+0.27 −0.21 × 10−5 is in agreement with results derived from Cassini CIRS and ISO/SWS observations, confirming the unexpectedly low CH3D abundance. Assuming a fractionation factor of 1.34 ± 0.19 we derive a hydrogen D/H of 1.23+0.27 −0.23 × 10−5. This value remains lower than previous tropospheric hydrogen D/H measurements of (i) Saturn 2.10(±0.13) × 10−5, (ii) Jupiter 2.6(±0.7) × 10−5 and (iii) the proto-solar hydrogen D/H of 2.1(±0.5) × 10−5, suggesting that the fractionation factor may not be appropriate for stratospheric methane, or that the D/H ratio in Saturn’s stratosphere is not representative of the bulk of the planet.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"70 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91371950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"When tension is just a fluctuation","authors":"B. Joachimi, F. Köhlinger, W. Handley, P. Lemos","doi":"10.1051/0004-6361/202039560","DOIUrl":"https://doi.org/10.1051/0004-6361/202039560","url":null,"abstract":"Summary statistics of the likelihood, such as the Bayesian evidence, offer a principled way of comparing models and assessing tension between, or within, the results of physical experiments. Noisy realisations of the data induce scatter in these model comparison statistics. For a realistic case of cosmological inference from large-scale structure we show that the logarithm of the Bayes factor attains scatter of order unity, increasing significantly with stronger tension between the models under comparison. We develop an approximate procedure that quantifies the sampling distribution of the evidence at small additional computational cost and apply it to real data to demonstrate the impact of the scatter, which acts to reduce the significance of any model discrepancies. Data compression is highlighted as a potential avenue to suppressing noise in the evidence to negligible levels, with a proof of concept on Planck cosmic microwave background data.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"16 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84299134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"High angular resolution polarimetric imaging of the nucleus of NGC 1068","authors":"L. Grosset, D. Rouan, F. Marin, D. Gratadour, E. Lagadec, S. Hunziker, M. Montargès, Y. Magnard, M. Carle, J. Pragt, C. Petit","doi":"10.1051/0004-6361/202038260","DOIUrl":"https://doi.org/10.1051/0004-6361/202038260","url":null,"abstract":"Polarisation is a decisive method to study the inner region of active galactic nuclei (AGNs) since it is not affected by contrast issues similarly to how classical imaging is. When coupled to high angular resolution (HAR), polarisation can help to disentangle the location of the various polarising mechanisms and then give an insight on the physics taking place on the core of AGNs. We obtained a new data set of HAR polarimetric images of the archetypal Seyfert 2 nucleus of NGC 1068 observed with SPHERE/VLT and we aim in this paper at presenting the polarisation maps and at spatially separating the location of the polarising mechanisms, thus deriving constraints on the organisation of the dust material in the inner region of this AGN. We then compared these measurements to radiative transfer simulations of scattering and dichroic absorption processes, using the Monte-Carlo code MontAGN. We establish a detailed table of the relative importance of the polarising mechanism as a function of the aperture and of the wavelength. We are able to separate the dominant polarising mechanisms in the three regions of the ionisation cone, the extended envelop of the torus and the very central bright source of the AGN. Thus, we estimate the contribution of the different polarisation mechanisms to the observed polarisation flux in these regions. Dichroic absorption is estimated to be responsible for about 99 % of the polarised flux coming from the photo-centre. However, this contribution would be restricted to this location only, double scattering process being the most important contributor to polarisation in the equatorial plane of the AGN and single scattering being dominant in the polar outflow bi-cone.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"100 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88942318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Systematic search for lensed X-ray sources in the CLASH fields","authors":"Ang Liu, P. Tozzi, P. Rosati, P. Bergamini, G. Caminha, R. Gilli, C. Grillo, M. Meneghetti, A. Mercurio, M. Nonino, E. Vanzella","doi":"10.1051/0004-6361/202040249","DOIUrl":"https://doi.org/10.1051/0004-6361/202040249","url":null,"abstract":"We search for unresolved X-ray emission from lensed sources in the FOV of 11 CLASH clusters with Chandra data. We consider the solid angle in the lens plane corresponding to a magnification $mu>1.5$, that amounts to a total of ~100 arcmin$^2$. Our main goal is to assess the efficiency of massive clusters as cosmic telescopes to explore the faint end of X-ray extragalactic source population. We search for X-ray emission from strongly lensed sources identified in the optical, and perform an untargeted detection of lensed X-ray sources. We detect X-ray emission only in 9 out of 849 lensed/background optical sources. The stacked emission of the sources without detection does not reveal any signal in any band. Based on the untargeted detection, we find 66 additional X-ray sources that are consistent with being lensed sources. After accounting for completeness and sky coverage, we measure for the first time the soft- and hard-band number counts of lensed X-ray sources. The results are consistent with current modelization of the AGN population distribution. The distribution of de-lensed fluxes of the sources identified in moderately deep CLASH fields reaches a flux limit of ~$10^{-16}$ and ~$10^{-15}$ erg/s/cm$^{2}$ in the soft and hard bands, respectively. We conclude that, in order to match the depth of the CDFS exploiting massive clusters as cosmic telescopes, the required number of cluster fields is about two orders of magnitude larger than that offered by the 20 years Chandra archive. A significant step forward will be made when future X-ray facilities, with ~1' angular resolution and large effective area, will allow the serendipitous discovery of rare, strongly lensed high-$z$ X-ray sources, enabling the study of faint AGN activity in early Universe and the measurement of gravitational time delays in the X-ray variability of multiply imaged AGN.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"16 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75182385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 possible far-ultraviolet flux-dependent core mass function in NGC 6357","authors":"J. Brand, A. Giannetti, F. Massi, J. Wouterloot, C. Verdirame","doi":"10.1051/0004-6361/202039506","DOIUrl":"https://doi.org/10.1051/0004-6361/202039506","url":null,"abstract":"To derive the properties of the dense cores in the galactic star-forming complex NGC6357 and to investigate the effects of an intense far-UV radiation field on their properties, we mapped the region at 450 and 850 micron, and in the CO(3-2) line with the JCMT. We also made use of the Herschel Hi-GAL data at 70 and 160 micron. We used Gaussclumps to retrieve 686 compact cores embedded in the diffuse sub-mm emission and constructed their SED from 70 to 850 micron, from which we derived mass and temperature. The estimated mass completeness limit is ~5Mo. We divided the observed area in an 'active' region, exposed to the far-UV radiation from the more massive members of three star clusters (411 cores), and a 'quiescent' region, less affected by far-UV radiation (275 cores). We also attempted to select a sample of pre-stellar cores based on cross-correlation with 70 micron emission and red WISE point sources. Most of the cores above the mass completeness limit are likely to be gravitationally bound. The fraction of gas in dense cores is very low, 1.4%. We found a mass-size relation log(M/Mo) ~ (2.0-2.4) x log (D/arcsec), depending on the precise selection of the sample. The temperature distributions in the two sub-regions are clearly different, peaking at ~25K in the quiescent region and at ~35K in the active region. The core mass functions are different as well, at a 2sigma level, consistent with a Salpeter IMF in the quiescent region and flatter than that in the active region. The dense cores lying close to the HII regions are consistent with pre-existing cores being gradually engulfed by a PDR and photoevaporating. We attribute the different global properties of dense cores in the two sub-regions to the influence of the far-UV radiation field.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"11 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82176924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Mysterious, variable, and extremely hot: White dwarfs showing ultra-high excitation lines","authors":"N. Reindl, V. Schaffenroth, Semih Filiz, S. Geier, I. Pelisoli, S. O. Kepler","doi":"10.1051/0004-6361/202140289","DOIUrl":"https://doi.org/10.1051/0004-6361/202140289","url":null,"abstract":"About 10% of all stars exhibit absorption lines of ultra-high excited (UHE) metals (e.g. OVIII) in their optical spectra when entering the white dwarf cooling sequence. The recent discovery of a both spectroscopic and photometric variable UHE white dwarf led to the speculation that the UHE lines might be created in a shock-heated circumstellar magnetosphere. We investigate (multi-band) light curves from several ground- and space-based surveys of all 16 currently known UHE white dwarfs (including one newly discovered) and eight white dwarfs that show only the HeII line problem, as both phenomena are believed to be connected. We find that $75^{+8}_{-13}$% of the UHE white dwarfs, and $75^{+9}_{-19}$% of the HeII line problem white dwarfs are significantly photometrically variable, with periods ranging from 0.22d to 2.93d and amplitudes from a few tenth to a few hundredth mag. The high variability rate is in stark contrast to the variability rate amongst normal hot white dwarfs (we find $9^{+4}_{-2}$%), marking UHE and HeII line problem white dwarfs as a new class of variable stars. The period distribution of our sample agrees with both the orbital period distribution of post-common envelope binaries and the rotational period distribution of magnetic white dwarfs if we assume that the objects in our sample will spin-up as a consequence of further contraction. The lack of increasing photometric amplitudes towards longer wavelengths, as well as the non-detection of optical emission lines arising from the highly irradiated face of a hypothetical secondary in the optical spectra of our stars, makes it seem unlikely that an irradiated late type companion is the origin of the photometric variability. Instead, we believe that spots on the surfaces of these stars and/or geometrical effects of circumstellar material might be responsible. (abridged)","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"34 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86826068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Detection of an ionized gas outflow in the extreme UV-luminous star-forming galaxy BOSS-EUVLG1 at z = 2.47","authors":"J. 'Alvarez-M'arquez, R. Marques-Chaves, L. Colina, I. P'erez-Fournon","doi":"10.1051/0004-6361/202039375","DOIUrl":"https://doi.org/10.1051/0004-6361/202039375","url":null,"abstract":"BOSS-EUVLG1 is the most ultraviolet (UV) and Ly$alpha$ luminous galaxy detected so far in the Universe, going through a very active starburst phase, and forming stars at a rate (SFR) of 955 $pm$ 118 M$_{odot}$ yr$^{-1}$. We report the detection of a broad H$alpha$ component carrying 25% of the total H$alpha$ flux. The broad H$alpha$ line traces a fast and massive ionized gas outflow characterized by a total mass, $log(M_{out}[M_{odot}]),$ of 7.94 $pm$ 0.15, an outflowing velocity (V$_{out}$) of 573 $pm$ 151 km s$^{-1}$, and an outflowing mass rate ($dot{M}_{out}$) of 44 $pm$ 20 M$_{odot}$ yr$^{-1}$. The presence of the outflow in BOSS-EUVLG1 is also supported by the identification of blueshifted UV absorption lines in low and high ionization states. The energy involved in the H$alpha$ outflow can be explained by the ongoing star formation without the need for an Active Galactic Nucleus. The derived low mass loading factor ($eta$= 0.05 $pm$ 0.03) indicates that although massive, this phase of the outflow can not be relevant for the quenching of the star formation. In addition, only a small fraction ($leq$ 15%) of the ionized outflowing material with velocities above 372 km s$^{-1}$ could escape the gravitational potential, and enrich the surrounding circum-galactic medium at distances above tens of kpc. The ionized phase of the outflow does not carry the mass and energy to play a relevant role neither in the evolution of the host galaxy nor in the enrichment of the intergalactic medium. Other phases of the outflow could be carrying most of the outflow energy and mass in the form of hot X-ray emitting gas as predicted by some recent simulations. The expected emission of the extended X-ray emitting halo associated with the outflow in BOSS-EUVLG1 and similar galaxies could be detected with the future X-ray observatory, {it ATHENA} but could not be resolved spatially.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"1 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85454001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Cosmological constraints on the magnification bias on sub-millimetre galaxies after large-scale bias corrections","authors":"J. González-Nuevo, M. M. Cueli, L. Bonavera, A. Lapi, M. Migliaccio, F. Argüeso, L. Toffolatti","doi":"10.1051/0004-6361/202039043","DOIUrl":"https://doi.org/10.1051/0004-6361/202039043","url":null,"abstract":"Context. The study of the magnification bias produced on high-redshift sub-millimetre galaxies by foreground galaxies through the analysis of the cross-correlation function was recently demonstrated as an interesting independent alternative to the weak-lensing shear as a cosmological probe.\u0000Aims. In the case of the proposed observable, most of the cosmological constraints mainly depend on the largest angular separation measurements. Therefore, we aim to study and correct the main large-scale biases that affect foreground and background galaxy samples to produce a robust estimation of the cross-correlation function. Then we analyse the corrected signal to derive updated cosmological constraints.\u0000Methods. We measured the large-scale, bias-corrected cross-correlation functions using a background sample of H-ATLAS galaxies with photometric redshifts > 1.2 and two different foreground samples (GAMA galaxies with spectroscopic redshifts or SDSS galaxies with photometric ones, both in the range 0.2 < z < 0.8). These measurements are modelled using the traditional halo model description that depends on both halo occupation distribution and cosmological parameters. We then estimated these parameters by performing a Markov chain Monte Carlo under multiple scenarios to study the performance of this observable and how to improve its results.\u0000Results. After the large-scale bias corrections, we obtain only minor improvements with respect to the previous magnification bias results, mainly confirming their conclusions: a lower bound on Ωm > 0.22 at 95% CL and an upper bound σ8 < 0.97 at 95% CL (results from the zspec sample). Neither the much higher surface density of the foreground photometric sample nor the assumption of Gaussian priors for the remaining unconstrained parameters significantly improve the derived constraints. However, by combining both foreground samples into a simplified tomographic analysis, we were able to obtain interesting constraints on the Ωm − σ8 plane as follows: Ωm = 0.50−0.20+0.14 and σ8 = 0.75−0.10+0.07 at 68% CL.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"48 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82128506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Overdensity of VVV galaxies behind the Galactic bulge","authors":"D. Galdeano, L. Pereyra, F. Duplancic, G. Coldwell, S. Alonso, A. Ruiz, S. Cora, N. Perez, C. Vega-Mart'inez, D. Minniti","doi":"10.1051/0004-6361/201937432","DOIUrl":"https://doi.org/10.1051/0004-6361/201937432","url":null,"abstract":"We studied a region of 1.636 square degrees corresponding to the VVV tile $b204$. Using SExtractor, we analysed photometric data generating a catalogue of extended sources in this area. In order to confirm these sources as galaxy candidates we visually inspected RGB images looking for typical galaxy features. Using 2MASX and GCMW catalogued sources we tested completeness and contamination of our catalogue and define suitable colour cuts to select galaxies. We also compared the observational results with those obtained from two semi-analytical models on Dark Matter simulations. One galaxy catalogue was constructed with the SAG semi-analytic model of galaxy formation, and the other one was constructed with the L-Galaxies semi-analytic model.By adopting CLASS-STAR$ 0.7$ arcsec and specific colour cuts (J-Ks$>$0.97, J-H$>$0 and H-Ks$>$0) we generated an automatic catalogue of extended sources. After visual inspection we identified 624 sources with 10$<$Ks$<$17 as galaxy candidates. The contamination of the automatic catalogue is 28% when considering visually confirmed galaxies as reliable objects. The estimated completeness is 87% up to magnitude Ks=13.5. We analysed the spatial distribution of galaxy candidates, finding a high concentration of galaxies in a small region of 15 arcmin radius. This region has three times higher density than similar areas in the tile. We compared the number of galaxies in this small area with the mean density values obtained from a suitable sample of galaxies from semi-analytic models finding that our results are consistent with an overdensity region. Using VVV near-infrared data and mock catalogues we detect new extragalactic sources that have not been identified by other catalogues. We demonstrate the potentiality of the VVV survey studying a large number of galaxy candidates and extragalactic structures obscured by the Milky Way.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"1 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83249956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}