Suchergebnisse

We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2 × 8.4 m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of μV ∼31 mag arcsec-2 (3σ in 10″ × 10″ boxes) of nearby galaxies. We simultaneously collected deep imaging in the g and r Sloan filters using the Large Binocular Cameras. The resulting images are 60 times (i.e. ∼4.5 mag) deeper than those from the Sloan Digital Sky Survey, and they have characteristics comparable (in depth and spatial resolution) to the ones expected from the future Legacy Survey of Space and Time (LSST). Here we show the first results of our pilot programme targeting NGC 1042 (an M 33 analogue at a distance of 13.5 Mpc) and its surroundings. The depth of the images allowed us to detect an asymmetric stellar halo in the outskirts of this galaxy whose mass (1.4 ± 0.4 × 108 M) is in agreement with the ΛCDM expectations. Additionally, we show that deep imaging from the LBT reveals low mass satellites (a few times 105 M) with very faint central surface brightness μV(0) ∼27 mag arcsec-2 (i.e. similar to Local Group dwarf spheroidals, such as Andromeda XIV or Sextans, but at distances well beyond the local volume). The depth and spatial resolution provided by the LIGHTS survey open up a unique opportunity to explore the 'missing satellites' problem in a large variety of galaxies beyond our Local Group down to masses where the difference between the theory and observation (if any) should be significant. © 2021 ESO. ; We acknowledge support from grant PID2019-107427GB-C32 from The Spanish Ministry of Science and Innovation. We acknowledge financial support from the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721463 to the SUNDIAL ITN network, and the European Regional Development Fund (FEDER), from IAC project P/300624, financed by the Ministry of Science, Innovation and Universities, through the State Budget and by the Canary Islands Department of Economy, Knowledge and Employment, through the Regional Budget of the Autonomous Community. DZ acknowledges financial support from NSF AST-2006785. NC acknowledges support from the research project grant "Understanding the Dynamic Universe" funded by the Knut and Alice Wallenberg Foundation under Dnr KAW 2018.0067 and Chris Usher for interesting comments. DJS acknowledges support from NSF grants AST-1821967 and 1813708. JR acknowledges funding from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), financial support from the grants AYA2015-65973-C3-1-R and RTI2018-096228B-C31 (MINECO/FEDER, UE) as well as support from the State Research Agency (AEI-MCINN) of the Spanish Ministry of Science and Innovation under the grant `The structure and evolution of galaxies and their central regions' with reference PID2019-105602GB-I00/10.13039/501100011033. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona Board of Regents; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, The Leibniz Institute for Astrophysics Potsdam, and Heidelberg University; The Ohio State University, representing OSU, University of Notre Dame, University of Minnesota and University of Virginia. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This work was partly done using GNU Astronomy Utilities (Gnuastro, ascl.net/1801.009) version 0.13.12-f50c. Work on Gnuastro has been funded by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) scholarship and its Grant-in-Aid for Scientific Research (21244012, 24253003), the European Research Council (ERC) advanced grant 339659-MUSICOS, and the Spanish Ministry of Economy and Competitiveness (MINECO) under grant number AYA2016-76219-P. ; Peer reviewed

In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad H beta line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Ha line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H beta width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad Ha velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H beta velocity shifted by similar to 250 km s(-1) over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise. ; National Science Foundation (NSF) AST-1108835, 1412693, 1107865, 1107812, 1412315, 1108665 ; NSF through the Graduate Research Fellowship Program ; NSF grant AST-1211916 ; Gary & Cynthia Bengier ; Richard & Rhoda Goldman Fund ; TABASGO Foundation ; Christopher R. Redlich Fund ; Packard Research Fellowship ; National Aeronautics and Space Administration (NASA) ; Gemini-CONICYT 32120009 ; NSF AST-1102845 ; National Research Foundation of Korea (NRF) grant - Korea government (MEST) 2012-006087 ; NSF Research at Undergraduate Institutions (RUI) grant AST-1312296 ; NSF Astronomy and Astrophysics Postdoctoral Fellowship AST-1302771 ; Grainger Foundation ; NASA ; Alfred P. Sloan Foundation ; NSF ; U.S. Department of Energy ; Japanese Monbukagakusho ; Max Planck Society ; Higher Education Funding Council for England ; Astronomy

The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including H beta and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. In both cases, the measured lag (tau(cen)) of Fe II is longer than that of H beta, although the inferred lags are somewhat sensitive to the choice of Fe II template used in the fit. For spectral decompositions done using the Fe II template of Veron-Cetty et al., we find tau(cen)(Fe II)/tau(cen)(H beta) = 1.9 +/- 0.6 in NGC 4593 and 1.5 +/- 0.3 in Mrk 1511. The detection of highly correlated variations between Fe II and continuum emission demonstrates that the Fe II emission in these galaxies originates in photoionized gas, located predominantly in the outer portion of the broad-line region. ; NSF AST-110812, 1107865, 1108665, 1108835, AST-1211916, AST-1102845, AST-0618209 ; Gary & Cynthia Bengier ; Richard & Rhoda Goldman Fund ; TABASGO Foundation ; Christopher R. Redlich Fund ; Packard Research Fellowship ; NASA ; National Research Foundation of Korea (NRF) ; Korea government (MEST) 2012-006087 ; McDonald Observatory