Article
Astronomy & Astrophysics
Dohyeong Kim, Daye Lee, Myungshin Im
Summary: Bolometric luminosity is a key indicator of the radiative energy output of an active galactic nucleus. Dust extinction can affect estimates based on ultraviolet or optical luminosities, so using infrared hydrogen Paschen and Brackett line luminosities to estimate bolometric luminosities can help reduce this impact.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yongjiang Wang, Wanqing Liu, Zhaohui Shang, Michael S. Brotherton
Summary: This study investigates the relationship between the equivalent width of broad emission lines and the underlying continuum luminosity in active galactic nuclei (AGNs), known as the Baldwin effect (BE), as well as the correlation with the Eddington ratio, referred to as the modified Baldwin effect (MBE). The results show that the BE is stronger than the MBE for most of the broad emission lines. Additionally, the study finds that the slope of the BE and MBE is related to the ionization energy of the lines. Furthermore, the O vi emission line is found to have a broader line width and larger blueshift compared to the C iv line, suggesting a closer proximity to the accretion disc and stronger influence from the accretion disc wind.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Daniel Kynoch, Hermine Landt, Maryam Dehghanian, Martin J. Ward, Gary J. Ferland
Summary: This study presents the first detailed investigation into the variability of the near-infrared coronal lines in AGN. It is found that the coronal lines in AGN are generally broader and blueshifted compared to low-ionization forbidden lines. The variability primarily occurs in the broad wings of the coronal line profiles, while the cores show negligible changes. This suggests the presence of at least two coronal line regions in AGN.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Reza Monadi, Simeon Bird
Summary: This study analyzes the C iv line features and color parameters of core ERQs and finds that they may represent a separate population. A new criterion for selecting ERQs is developed, resulting in the identification of more quasars with C iv broad absorption line features. These selected quasars are confirmed to be extreme objects in the intersection of the WISE AGN catalog and the MILLIQUAS quasar catalog in the color-color space.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
C. G. Bornancini, G. A. Oio, M. V. Alonso, D. Garcia Lambas
Summary: This study investigates the properties of galaxies hosting AGNs identified at mid- and near-IR wavelengths and confirms their selection using optical spectroscopy and X-ray photometry. The results show that the methods using a combination of mid- and near-IR observations with power-law emission have the greatest success in selecting AGNs. Additionally, AGN samples have a higher percentage of galaxy morphologies with bulge+disk components based on morphological studies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Xinfeng Xu, Nahum Arav, Timothy Miller, Kirk T. Korista, Chris Benn
Summary: The study of quasar Q0059-2735 revealed a variety of outflow absorption features, including wide and narrow absorption lines formed by high and low-ionization transitions. By fitting the absorption troughs, the physical conditions of the outflows and the presence of iron-peak elements were determined. The research also uncovered the distance of the outflows to the central quasar and the smallest outflow deceleration in any known quasars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Juan A. Fernandez-Ontiveros, Teo Munoz-Darias
Summary: The luminosity-excitation diagram (LED) based on mid-infrared nebular line fluxes reveals accretion states in active galactic nuclei (AGN). Soft state and hard state mainly appear in low-luminosity AGN, characterized by disc-dominated nuclei and nuclei with negligible disc contributions, respectively.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
XueGuang Zhang
Summary: In this paper, a potential sub-pc binary black hole (BBH) system in SDSS J1257+2023 is reported based on different properties of broad Balmer emission lines. The broad Hα line in SDSS J1257+2023 is significantly broader than the broad Hβ line, with a width ratio of 0.69, which is quite different from the normal line width ratio of 1.1 in quasars. The broader component in the broad Hα line can be confidently confirmed through the F-test technique and different model functions. The detection of optical quasi-periodic oscillations (QPOs) with a periodicity of about 1000 days in the BBH system of SDSS J1257+2023 is supported by the Zwicky Transient Facility (ZTF) light curves and the generalized Lomb-Scargle periodogram with a confidence level higher than 3σ.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
T. M. Buendia-Rios, C. A. Negrete, P. Marziani, D. Dultzin
Summary: By studying 309 quasars, we have found that Al III and C III] can be reliable virial mass estimators for Pop. A and Pop. B objects, providing consistent mass estimations.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
XueGuang Zhang, Qi Zheng
Summary: In this paper, a method is proposed to test dual-core systems for double-peaked narrow emission lines. The main galaxy has a dual-core system with double-peaked narrow Balmer lines, while the companion galaxy has single-peaked narrow Balmer lines. The study of SDSS J2219-0938 reveals a different flux ratio between the emission components, disfavoring a dual-core system for the double-peaked narrow Balmer emission lines.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jian-Min Wang, Pu Du, Yu-Yang Songsheng, Yan-Rong Li
Summary: Spiral arms in broad emission lines provide information about ionized gas in BLRs. The radius of BLRs overlaps with that of accretion disks, and the resulting spiral arms lead to various profiles of broad emission lines.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
X. G. Zhang
Summary: In this study, we discuss the properties of a mis-classified quasar, SDSS J1451+2709, which is classified as a H ii galaxy in the BPT diagram. By measuring its emission lines, we find that different model functions lead to different determined fluxes, but the different flux ratios of narrow emission lines classify it as a H ii galaxy. Two methods are proposed to explain the unique properties, but further research is needed to find the physical origin.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Letter
Astronomy & Astrophysics
Giulia Tozzi, Elisabeta Lusso, Lapo Casetti, Marco Romoli, Gloria Andreuzzi, Isabel Montoya Arroyave, Emanuele Nardini, Giovanni Cresci, Riccardo Middei, Silvia Bertolini, Paolo Calabretto, Vieri Cammelli, Francisco Cuadra, Marco Dalla Ragione, Cosimo Marconcini, Adriano Miceli, Irene Mini, Martina Palazzini, Giorgio Rotellini, Andrea Saccardi, Lavinia Sama, Mattia Sangalli, Lorenzo Serafini, Fabio Spaccino
Summary: This study reports on the changing appearance of the active galactic nucleus (AGN) in NGC 4156, discovered through data acquired in 2019. Previous optical spectra did not show any broad-line emission, and the AGN was only observed through X-ray observations. However, the 2019 data unexpectedly revealed broad-line components and an increase in the continuum, indicating a transition from a type 2 to a (nearly) type 1 AGN. Follow-up observations in 2022 confirmed the broad-line emission but did not detect the rising continuum, suggesting a further evolution towards a (nearly) type 2 AGN. This study also provided the first estimate of the black hole mass in this source. The observed spectral variability could be attributed to changes in the accretion activity of NGC 4156.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Jelena Kovacevic-Dojcinovic, Ivan Dojcinovic, Masa Lakicevic, Luka C. Popovic
Summary: This study analyzes the influence of outflow kinematics on different emission lines in active galactic nuclei. The results show strong correlations between the widths and shifts of the wing components of various lines, indicating that outflow dynamics systematically affect all emission lines in the spectrum. The [O III] lines exhibit the strongest outflow signature, while the [S II] lines show the weakest.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Pu Du, Jian-Min Wang
Summary: There is evidence of regular substructures, such as spiral arms, in broad-line regions (BLRs) of active galactic nuclei (AGNs), which are consistent with self-gravitating regions of accretion disks. This study investigates the loosely wound spiral arms excited by gravitational instabilities and their observational characteristics in disk-like BLRs. The results show that these spiral arms can explain various phenomena observed, including asymmetries in emission-line profiles, complex subfeatures in velocity-delay maps, and short timescales of asymmetry changes in emission-line profiles.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
K. Iwasawa, A. Comastri, C. Vignali, R. Gilli, G. Lanzuisi, W. N. Brandt, P. Tozzi, M. Brusa, F. J. Carrera, P. Ranalli, V Mainieri, I Georgantopoulos, S. Puccetti, M. Paolillo
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
R. Nanni, R. Gilli, C. Vignali, M. Mignoli, A. Peca, S. Marchesi, M. Annunziatella, M. Brusa, F. Calura, N. Cappelluti, M. Chiaberge, A. Comastri, K. Iwasawa, G. Lanzuisi, E. Liuzzo, D. Marchesini, I. Prandoni, P. Tozzi, F. Vito, G. Zamorani, C. Norman
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
Marco Mignoli, Roberto Gilli, Roberto Decarli, Eros Vanzella, Barbara Balmaverde, Nico Cappelluti, Letizia P. Cassara, Andrea Comastri, Felice Cusano, Kazushi Iwasawa, Stefano Marchesi, Isabella Prandoni, Cristian Vignali, Fabio Vito, Giovanni Zamorani, Marco Chiaberge, Colin Norman
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
J. Wolf, K. Nandra, M. Salvato, T. Liu, J. Buchner, M. Brusa, D. N. Hoang, V Moss, R. Arcodia, M. Brueggen, J. Comparat, F. de Gasperin, A. Georgakakis, A. Hotan, G. Lamer, A. Merloni, A. Rau, H. J. A. Rottgering, T. W. Shimwell, T. Urrutia, M. Whiting, W. L. Williams
Summary: High-redshift quasars provide clues to the early accretion history of the Universe, with X-ray observations offering less absorption and a more comprehensive view of these luminous sources compared to optical methods. The ongoing eROSITA X-ray survey has unveiled a high-z quasar population, shedding light on the X-ray luminosity function and the evolutionary history of these celestial objects. Radio observations have also provided insights into the nature of these high-redshift quasars, suggesting a potentially larger population of X-ray luminous AGNs than previously thought.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
F. Vito, W. N. Brandt, F. Ricci, E. Congiu, T. Connor, E. Banados, F. E. Bauer, R. Gilli, B. Luo, C. Mazzucchelli, M. Mignoli, O. Shemmer, C. Vignali, F. Calura, A. Comastri, R. Decarli, S. Gallerani, R. Nanni, M. Brusa, N. Cappelluti, F. Civano, G. Zamorani
Summary: Observations of the z=6.515 radio-quiet QSO PSO167-13 aim to confirm the existence of a heavily obscured X-ray source and investigate the rest-frame UV properties of the QSO. The lack of significant X-ray emission from the system suggests intrinsic weakness or small-scale absorption by Compton-thick material, with the possibility of nuclear winds contributing to its X-ray weakness.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
S. Marchesi, M. Mignoli, R. Gilli, A. Peca, M. Bolzonella, R. Nanni, M. Annunziatella, B. Balmaverde, M. Brusa, F. Calura, L. P. Cassara, M. Chiaberge, A. Comastri, F. Cusano, Q. D'Amato, K. Iwasawa, G. Lanzuisi, D. Marchesini, T. Morishita, I. Prandoni, A. Rossi, P. Tozzi, C. Vignali, F. Vito, G. Zamorani, C. Norman
Summary: The research team publicly released the spectroscopic and photometric redshift catalog of sources detected with Chandra in the z=6.3 quasar SDSS J1030+0525 field. They found that X-ray-selected AGNs can efficiently track large-scale structures and there may be a potential source excess at z>=4, which needs to be confirmed or rejected in the near future with dedicated spectroscopic campaigns.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Qingling Ni, W. N. Brandt, Chien-Ting Chen, Bin Luo, Kristina Nyland, Guang Yang, Fan Zou, James Aird, David M. Alexander, Franz Erik Bauer, Mark Lacy, Bret D. Lehmer, Labani Mallick, Mara Salvato, Donald P. Schneider, Paolo Tozzi, Iris Traulsen, Mattia Vaccari, Cristian Vignali, Fabio Vito, Yongquan Xue, Manda Banerji, Kate Chow, Andrea Comastri, Agnese Del Moro, Roberto Gilli, James Mullaney, Maurizio Paolillo, Axel Schwope, Ohad Shemmer, Mouyuan Sun, John D. Timlin III, Jonathan R. Trump
Summary: This study presents X-ray point-source catalogs in the W-CDF-S and ELAIS-S1 fields, aiming to bridge the gap between deep pencil-beam X-ray surveys and shallow surveys over large areas. The XMM-Newton observations in these regions detected a significant number of X-ray sources, with reliable optical-to-IR multiwavelength counterpart candidates identified for a high percentage of them. Additionally, photometric redshift information is provided for the X-ray sources detected in these fields.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2021)
Article
Astronomy & Astrophysics
N. Torres-Alba, S. Marchesi, X. Zhao, M. Ajello, R. Silver, T. T. Ananna, M. Balokovic, P. B. Boorman, A. Comastri, R. Gilli, G. Lanzuisi, K. Murphy, C. M. Urry, C. Vignali
Summary: In this study, simultaneous analysis of NuSTAR and XMM-Newton data of eight CT-AGN candidates selected in the Swift-BAT 100 month catalog was conducted. The results confirmed five CT-AGN, representing an increase compared to previous observations. The importance of using NuSTAR data to confirm CT-AGN in the local universe was highlighted.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
E. Bertola, C. Vignali, G. Lanzuisi, M. Dadina, M. Cappi, R. Gilli, G. A. Matzeu, G. Chartas, E. Piconcelli, A. Comastri
Summary: We present new joint XMM-Newton and NuSTAR observations of the gravitationally-lensed broad-absorption line quasar APM 08279+5255 (z = 3.91). The latest X-ray exposures show a fainter state and a prominent Fe K alpha emission line without significant absorption. This allows us to measure X-ray reflection and the high-energy cutoff in this source for the first time.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
R. Gilli, C. Norman, F. Calura, F. Vito, R. Decarli, S. Marchesi, K. Iwasawa, A. Comastri, G. Lanzuisi, F. Pozzi, Q. D'Amato, C. Vignali, M. Brusa, M. Mignoli, P. Cox
Summary: We combine results from deep ALMA observations to show that the column density of interstellar medium (ISM) in massive galaxies rapidly increases toward early cosmic epochs. Our study suggests that supermassive black holes in the early Universe are primarily hidden by the ISM in their host galaxies. We have developed an analytic model that successfully reproduces the increase in obscured AGN fraction with redshift observed in deep X-ray surveys. The observed X-ray nebulae impose stringent design constraints on the spatial resolution of future X-ray imaging observatories.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
R. Silver, N. Torres-Alba, X. Zhao, S. Marchesi, A. Pizzetti, M. Ajello, G. Cusumano, V La Parola, A. Segreto, A. Comastri
Summary: In this study, we conducted a spectral analysis of nine low-redshift AGN and found that all of them are heavily obscured, with two of them confirmed to be Compton-thick AGN. We also examined the effectiveness of different selection criteria in discovering CT-AGN in the local Universe, finding that our criteria has a much higher success rate compared to blind surveys.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
A. Pensabene, P. van der Werf, R. Decarli, E. Banados, R. A. Meyer, D. Riechers, B. Venemans, F. Walter, A. Weiss, M. Brusa, X. Fan, F. Wang, J. Yang
Summary: This study investigates the water vapor emission in distant galaxies and explores its potential as a tracer for star formation activity in the warm and dense phase of the interstellar medium. The researchers present observational data and modeling results, highlighting the excitation conditions and the interplay between collisions and infrared pumping in high-redshift quasar host galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Marchesi, X. Zhao, N. Torres-Alba, M. Ajello, M. Gaspari, A. Pizzetti, J. Buchner, E. Bertola, A. Comastri, A. Feltre, R. Gilli, G. Lanzuisi, G. Matzeu, F. Pozzi, F. Salvestrini, D. Sengupta, R. Silver, F. Tombesi, A. Traina, C. Vignali, L. Zappacosta
Summary: In this study, multi-epoch monitoring of NGC 1358 using NuSTAR and XMM-Newton revealed its changing-look nature and the variability of column density. The results also showed a tentative anticorrelation between column density and luminosity. The study demonstrated the effectiveness of multi-epoch monitoring with NuSTAR and XMM-Newton in selecting heavily obscured AGN and provided insights for AGN feeding models.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Alessandro Peca, Cristian Vignali, Roberto Gilli, Marco Mignoli, Riccardo Nanni, Stefano Marchesi, Micol Bolzonella, Marcella Brusa, Nico Cappelluti, Andrea Comastri, Giorgio Lanzuisi, Fabio Vito
Summary: This study presents a method to constrain the redshifts of obscured active galactic nuclei based on low count statistics X-ray spectra. Reliable X-ray redshift solutions are estimated by taking advantage of main features in obscured AGN spectra and compared with photometric redshifts. Combining redshift solutions from both techniques improves accuracy, suggesting the procedure can be applied to sources detected only in X-rays or with uncertain redshifts.
ASTROPHYSICAL JOURNAL
(2021)
