Browsing by Author "Bauer, Franz"

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    A multiwavelength-motivated X-ray model for the Circinus Galaxy
    (2022) Andonie, Carolina; Ricci, Claudio; Paltani, Stéphane; Arévalo, Patricia; Treister, Ezequiel; Bauer, Franz; Stalevski, Marko
    Reprocessed X-ray emission in active galactic nuclei can provide fundamental information about the circumnuclear environments of supermassive black holes. Recent mid-infrared studies have shown evidence of an extended dusty structure perpendicular to the torus plane. In this work, we build a self-consistent X-ray model for the Circinus Galaxy including the different physical components observed at different wavelengths and needed to reproduce both the morphological and spectral properties of this object in the mid-infrared. The model consists of four components: the accretion disc, the broad-line region (BLR), a flared disc in the equatorial plane, and a hollow cone in the polar direction. Our final model reproduces well the 3-70 keV Chandra and NuSTAR spectra of Circinus, including the complex Fe K alpha zone and the spectral curvature, although several additional Gaussian lines, associated with either ionized iron or broadened Fe K alpha/K beta lines, are needed. We find that the flared disc is Compton-thick (N-H,N-d = 1.01(-0.24)(+0.03) x 10(25) cm(-2)) and geometrically thick (CF = 0.55(-0.05)(+0.01)), and that the hollow cone has a Compton-thin column density (N-H,N-c = 2.18(-0.43)(+0.47) x 10(23) cm(-2)), which is consistent with the values inferred by mid-infrared studies. Including also the BLR, the effective line-of-sight column density is NH = 1.47(-0.24)(+0.03) x 10(25) cm(-2). This approach to X-ray modelling, i.e. including all the different reprocessing structures, will be very important to fully exploit data from future X-ray missions.
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    JWST Insight into a Lensed HST-dark Galaxy and Its Quiescent Companion at z=2.58
    (2023) Kokorev, Vasily; Jin, Shuowen; Magdis, Georgios E.; Caputi, Karina I.; Valentino, Francesco; Dayal, Pratika; Trebitsch, Maxime; Brammer, Gabriel; Fujimoto, Seiji; Bauer, Franz; Iani, Edoardo; Kohno, Kotaro; Sese, David Blanquez; Gomez-Guijarro, Carlos; Rinaldi, Pierluigi; Navarro-Carrera, Rafael
    Using the novel James Webb Space Telescope (JWST)/NIRCam observations in the A2744 field, we present a first spatially resolved overview of a Hubble Space Telescope (HST)-dark galaxy, spectroscopically confirmed at z = 2.58 with magnification mu approximate to 1.9. While being largely invisible at similar to 1 mu m with NIRCam, except for sparse clumpy substructures, the object is well detected and resolved in the long-wavelength bands with a spiral shape clearly visible in F277W. By combining ancillary Atacama Large Millimeter/submillimeter Array (ALMA) and Herschel data, we infer that this object is an edge-on dusty spiral with an intrinsic stellar mass log (M (*)/M (circle dot)) similar to 11.3 and a dust-obscured star formation rate similar to 300 M (circle dot) yr(-1). A massive quiescent galaxy (log (M (*)/M (circle dot)) similar to 10.8) with tidal features lies 2.'' 0 away (r similar to 9 kpc), at a consistent redshift as inferred by JWST photometry, indicating a potential major merger. The dusty spiral lies on the main sequence of star formation, and shows high dust attenuation in the optical (3 < A ( V ) < 4.5). In the far-infrared, its integrated dust spectral energy distribution is optically thick up to lambda (0) similar to 500 mu m, further supporting the extremely dusty nature. Spatially resolved analysis of the HST-dark galaxy reveals a largely uniform A ( V ) similar to 4 area spanning similar to 57 kpc(2), which spatially matches to the ALMA 1 mm continuum emission. Accounting for the surface brightness dimming and the depths of current JWST surveys, unlensed analogs of the HST-dark galaxy at z > 4 would be only detectable in F356W and F444W in an UNCOVER-like survey, and become totally JWST-dark at z similar to 6. This suggests that detecting highly attenuated galaxies in the Epoch of Reionization might be a challenging task for JWST.
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    The high energy X-ray probe (HEX-P): Resolving the nature of Sgr A* flares, compact object binaries and diffuse X-ray emission in the Galactic center and beyond
    (2024) Mori, Kaya; Ponti, Gabriele; Bachetti, Matteo; Bodaghee, Arash; Grindlay, Jonathan; Hong, Jaesub; Krivonos, Roman; Kuznetsova, Ekaterina; Mandel, Shifra; Rodriguez, Antonio; Stel, Giovanni; Zhang, Shuo; Bao, Tong; Bauer, Franz; Clavel, Maica; Coughenour, Benjamin; Garcia, Javier A.; Gerber, Julian; Grefenstette, Brian; Jaodand, Amruta; Lehmer, Bret; Madsen, Kristin; Nynka, Melania; Predehl, Peter; Salcedo, Ciro; Stern, Daniel; Tomsick, John
    HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10 '' FWHM) and broad spectral coverage (0.2-80 keV) with an effective area far superior to current facilities' (including XMM-Newton and NuSTAR). These capabilities will enable revolutionary new insights into a variety of important astrophysical problems. We present scientific objectives and simulations of HEX-P observations of the Galactic Center (GC) and Bulge. We demonstrate the unique and powerful capabilities of the HEX-P observatory for studying both X-ray point sources and diffuse X-ray emission. HEX-P will be uniquely equipped to explore a variety of major topics in Galactic astrophysics, allowing us to 1) investigate broad-band properties of X-ray flares emitted from the supermassive black hole (BH) at Sgr A* and probe the associated particle acceleration and emission mechanisms; 2) identify hard X-ray sources detected by NuSTAR and determine X-ray point source populations in different regions and luminosity ranges; 3) determine the distribution of compact object binaries in the nuclear star cluster and the composition of the Galactic Ridge X-ray emission; 4) identify X-ray transients and measure fundamental parameters such as black hole spin; 5) find hidden pulsars in the Galactic Center; 6) search for BH-OB binaries and hard X-ray flares from young stellar objects in young massive clusters; 7) measure white dwarf (WD) masses of magnetic CVs to deepen our understanding of CV evolution and the origin of white dwarf magnetic fields; 8) explore primary particle accelerators in the GC in synergy with future TeV and neutrino observatories; 9) map out cosmic-ray distributions by observing non-thermal X-ray filaments; 10) explore past X-ray outbursts from Sgr A* through X-ray reflection components from giant molecular clouds.
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    The One-hundred-deg2 DECam Imaging in Narrowbands (ODIN): Survey Design and Science Goals
    (2024) Lee, Kyoung-Soo; Gawiser, Eric; Park, Changbom; Yang, Yujin; Valdes, Francisco; Lang, Dustin; Ramakrishnan, Vandana; Moon, Byeongha; Firestone, Nicole; Appleby, Stephen; Artale, Maria Celeste; Andrews, Moira; Bauer, Franz; Benda, Barbara; Broussard, Adam; Chiang, Yi-Kuan; Ciardullo, Robin; Dey, Arjun; Farooq, Rameen; Gronwall, Caryl; Guaita, Lucia; Huang, Yun; Hwang, Ho Seong; Im, Sang Hyeok; Jeong, Woong-Seob; Karthikeyan, Shreya; Kim, Hwihyun; Kim, Seongjae; Kumar, Ankit; Nagaraj, Gautam R.; Nantais, Julie; Padilla, Nelson; Park, Jaehong; Pope, Alexandra; Popescu, Roxana; Schlegel, David; Seo, Eunsuk; Singh, Akriti; Song, Hyunmi; Troncoso, Paulina; Vivas, A. Katherina; Zabludoff, Ann; Zenteno, Alfredo
    We describe the survey design and science goals for One-hundred-deg(2) DECam Imaging in Narrowbands (ODIN), a NOIRLab survey using the Dark Energy Camera (DECam) to obtain deep (AB similar to 25.7) narrowband images over an unprecedented area of sky. The three custom-built narrowband filters, N419, N501, and N673, have central wavelengths of 419, 501, and 673 nm and respective FWHM of 7.5, 7.6, and 10.0 nm, corresponding to Ly alpha at z = 2.4, 3.1, and 4.5 and cosmic times of 2.8, 2.1, and 1.4 Gyr, respectively. When combined with even deeper, public broadband data from the Hyper Suprime-Cam, DECam, and in the future, the Legacy Survey of Space and Time, the ODIN narrowband images will enable the selection of over 100,000 Ly alpha-emitting (LAE) galaxies at these epochs. ODIN-selected LAEs will identify protoclusters as galaxy overdensities, and the deep narrowband images enable detection of highly extended Ly alpha blobs (LABs). Primary science goals include measuring the clustering strength and dark matter halo connection of LAEs, LABs, and protoclusters, and their respective relationship to filaments in the cosmic web. The three epochs allow for the redshift evolution of these properties to be determined during the period known as Cosmic Noon, where star formation was at its peak. The narrowband filter wavelengths are designed to enable interloper rejection and further scientific studies by revealing [O II] and [O III] at z = 0.34, Ly alpha and He II 1640 at z = 3.1, and Lyman continuum plus Ly alpha at z = 4.5. Ancillary science includes similar studies of the lower-redshift emission-line galaxy samples and investigations of nearby star-forming galaxies resolved into numerous [O III] and [S II] emitting regions.