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The second Fermi-LAT source catalog (2FGL) is the deepest survey of the gamma-ray sky ever compiled, containing 1873 sources that constitute a very complete sample down to an energy flux of about 10^(-11) erg cm^(-2) s^(-1). While…

High Energy Astrophysical Phenomena · Physics 2013-07-01 M. Doert , M. Errando

We construct the rest-frame 2--10 keV intrinsic X-ray luminosity function of Active Galactic Nuclei (AGNs) from a combination of X-ray surveys from the all-sky Swift BAT survey to the Chandra Deep Field-South. We use ~3200 AGNs in our…

The Active Galactic Nuclei (AGN) glossary is vast and complex. Depending on selection method, observing wavelength, and brightness, AGNs are assigned distinct labels, yet the relationship between different selection methods and the…

Supervised artificial neural networks are used to predict useful properties of galaxies in the Sloan Digital Sky Survey, in this instance morphological classifications, spectral types and redshifts. By giving the trained networks unseen…

We present an analysis of importance feature selection applied to photometric redshift estimation using the machine learning architecture Decision Trees with the ensemble learning routine Adaboost (hereafter RDF). We select a list of 85…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Ben Hoyle , Markus Michael Rau , Roman Zitlau , Stella Seitz , Jochen Weller

We present a procedure to constrain the redshifts of obscured ($N_H > 10^{22}$ cm$^{-2}$) Active Galactic Nuclei (AGN) based on low-count statistics X-ray spectra, which can be adopted when photometric and/or spectroscopic redshifts are…

The recent increase in volume and complexity of available astronomical data has led to a wide use of supervised machine learning techniques. Active learning strategies have been proposed as an alternative to optimize the distribution of…

We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the Active Galactic Nuclei (AGN) detected by Fermi during its first year of operation, with the largest datasets ever used for this…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 M. Ackermann , M. Ajello , A. Allafort , E. Angelakis , M. Axelsson , L. Baldini , J. Ballet , G. Barbiellini , D. Bastieri , R. Bellazzini , B. Berenji , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , A. Bouvier , J. Bregeon , A. Brez , M. Brigida , P. Bruel , R. Buehler , S. Buson , G. A. Caliandro , R. A. Cameron , A. Cannon , P. A. Caraveo , J. M. Casandjian , E. Cavazzuti , C. Cecchi , E. Charles , A. Chekhtman , C. C. Cheung , S. Ciprini , R. Claus , J. Cohen-Tanugi , S. Cutini , F. de Palma , C. D. Dermer , E. do Couto e Silva , P. S. Drell , R. Dubois , D. Dumora , L. Escande , C. Favuzzi , S. J. Fegan , W. B. Focke , P. Fortin , M. Frailis , L. Fuhrmann , Y. Fukazawa , P. Fusco , F. Gargano , D. Gasparrini , N. Gehrels , N. Giglietto , P. Giommi , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , P. Grandi , I. A. Grenier , S. Guiriec , D. Hadasch , M. Hayashida , E. Hays , S. E. Healey , G. J , A. S. Johnson , T. Kamae , H. Katagiri , J. Kataoka , J. Kn , M. Kuss , J. Lande , S. -H. Lee , F. Longo , F. Loparco , B. Lott , M. N. Lovellette , P. Lubrano , A. Makeev , W. Max-Moerbeck , M. N. Mazziotta , J. E. McEnery , J. Mehault , P. F. Michelson , T. Mizuno , C. Monte , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , M. Naumann-Godo , S. Nishino , P. L. Nolan , J. P. Norris , E. Nuss , T. Ohsugi , A. Okumura , N. Omodei , E. Orlando , J. F. Ormes , M. Ozaki , D. Paneque , V. Pavlidou , V. Pelassa , M. Pepe , M. Pesce-Rollins , M. Pierbattista , F. Piron , T. A. Porter , S. Rain , M. Razzano , A. Readhead , A. Reimer , O. Reimer , J. L. Richards , R. W. Romani , H. F. -W. Sadrozinski , J. D. Scargle , C. Sgr , E. J. Siskind , P. D. Smith , G. Spandre , P. Spinelli , M. S. Strickman , D. J. Suson , H. Takahashi , T. Tanaka , G. B. Taylor , J. G. Thayer , J. B. Thayer , D. J. Thompson , D. F. Torres , G. Tosti , A. Tramacere , E. Troja , J. Vandenbroucke , G. Vianello , V. Vitale , A. P. Waite , P. Wang , B. L. Winer , K. S. Wood , Z. Yang , M. Ziegler

Empirical "backward" galaxy evolution models for infrared bright galaxies are constrained using multi-band infrared surveys. We developed a new Monte-Carlo algorithm for this task, implementing luminosity dependent distribution functions…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-15 E. Valiante , D. Lutz , E. Sturm , R. Genzel , E. Chapin

[Abbreviated] Upcoming large area sky surveys like EUCLID and eROSITA crucially depend on accurate photometric redshifts (photo-z). The identification of variable sources, such as AGNs, and the achievable redshift accuracy for varying…

[Abridged] We present a comprehensive investigation of the cosmological evolution of the luminosity function (LF) of galaxies and active galactic nuclei (AGN) in the infrared (IR). Based on the observed dichotomy in the ages of stellar…

We present a method for automated classification of galaxies with low signal-to-noise (S/N) spectra typical of redshift surveys. We develop spectral simulations based on the parameters for the 2dF Galaxy Redshift Survey, and with these…

Astrophysics · Physics 2015-06-24 S. R. Folkes , O. Lahav , S. J. Maddox

In the era of huge astronomical surveys, machine learning offers promising solutions for the efficient estimation of galaxy properties. The traditional, `supervised' paradigm for the application of machine learning involves training a model…

Astrophysics of Galaxies · Physics 2022-12-21 A. Humphrey , P. A. C. Cunha , A. Paulino-Afonso , S. Amarantidis , R. Carvajal , J. M. Gomes , I. Matute , P. Papaderos

The 21 cm signal from the Epoch of Reionization should be observed within the next decade. While a simple statistical detection is expected with SKA pathfinders, the SKA will hopefully produce a full 3D mapping of the signal. To extract…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-28 Hayato Shimabukuro , Benoit Semelin

We use $\sim 1,000$ X-ray sources in the COSMOS-Legacy survey and study the position of the AGN relative to the star forming main sequence (MS). We also construct a galaxy (non-AGN) reference sample that includes $\sim 90,000$ sources. We…

Astrophysics of Galaxies · Physics 2022-05-18 G. Mountrichas , V. A. Masoura , E. M. Xilouris , I. Georgantopoulos , V. Buat , E. -D. Paspaliaris

Variability is a property shared by virtually all active galactic nuclei (AGNs), and was adopted as a criterion for their selection using data from multi epoch surveys. Low Luminosity AGNs (LLAGNs) are contaminated by the light of their…

Astrophysics · Physics 2009-11-13 D. Trevese , K. Boutsia , F. Vagnetti , E. Cappellaro , S. Puccetti

In this study, we present a modelling of the X-ray emission from the simulated SMBHs within the cosmological hydrodynamical Magneticum Pathfinder Simulation, in order to study the statistical properties of the resulting X-ray Active…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-26 V. Biffi , K. Dolag , A. Merloni

Active galactic nuclei (AGN) are supermassive black holes with luminous accretion disks found in some galaxies, and are thought to play an important role in galaxy evolution. However, traditional optical spectroscopy for identifying AGN…

Astrophysics of Galaxies · Physics 2022-12-16 Ziting Guo , John F. Wu , Chelsea E. Sharon

Thanks to the advances in robotic telescopes, the time domain astronomy leads to a large number of transient events detected in images every night. Data mining and machine learning tools used for object classification are presented. The…

Instrumentation and Methods for Astrophysics · Physics 2015-11-17 Martin Topinka
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