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An active galactic nucleus recognition model based on deep neural network
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +21 more
To understand the cosmic accretion history of supermassive black holes, separating the radiation from active galactic nuclei (AGNs) and star-forming galaxies (SFGs) is critical. However, a reliable solution on photometrically recognizing AGNs still remains unsolved. In this work, we present a novel AGN recognition method based on Deep Neural Netwo…
Supermassive Binary Black Holes and the Case of OJ 287
Ciprini, S.; Nowak, M. A.; Komossa, S. +12 more
Supermassive binary black holes (SMBBHs) are laboratories par excellence for relativistic effects, including precession effects in the Kerr metric and the emission of gravitational waves. Binaries form in the course of galaxy mergers, and are a key component in our understanding of galaxy evolution. Dedicated searches for SMBBHs in all stages of t…
PS J1721+8842: a gravitationally lensed dual AGN system at redshift 2.37 with two radio components
Vegetti, S.; McKean, J. P.; Stacey, H. R. +4 more
Dual-Active Galactic Nuclei (AGN) are a natural consequence of the hierarchical structure formation scenario, and can provide an important test of various models for black hole growth. However, due to their rarity and difficulty to find at high redshift, very few confirmed dual-AGN are known at the epoch where galaxy formation peaks. Here we repor…
Discovery of soft and hard X-ray time lags in low-mass AGNs
Stalin, C. S.; De Marco, B.; Alston, W. N. +5 more
The scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying physical mechanism at work in accreting BH systems spanning a broad range of mass. However, the low-mass end of AGNs has never been explored in detail. In this work, we ext…
In the Trenches of the Solar-stellar Connection. IV. Solar Full-disk Scans of C II, Si IV, and Mg II by the Interface Region Imaging Spectrograph
Testa, Paola; De Pontieu, Bart; Ayres, Thomas
About once a month, the Interface Region Imaging Spectrograph conducts day-long raster scans of the full Sun in three ultraviolet spectral channels. These full-disk mosaics are valuable in the solar context, but provide a unique connection to the distant, unresolved stars. Here, 10 deep-exposure scans (4-8 s per slit step), collected during the pe…
Low-energy electromagnetic processes affecting free-falling test-mass charging for LISA and future space interferometers
Grimani, Catia; Villani, Mattia; Fabi, Michele +1 more
Galactic cosmic rays and solar energetic particles charge gold-platinum, free-falling test masses (TMs) on board interferometers for the detection of gravitational waves in space. The charging process induces spurious forces on the test masses that affect the sensitivity of these instruments mainly below 10-3 Hz. Geant4 and FLUKA Monte …
In the Trenches of the Solar-Stellar Connection. III. The HST/COS Ecliptic-poles Stellar Survey (EclipSS)
Ayres, Thomas R.
The Ecliptic-poles Stellar Survey (EclipSS) collected far-ultraviolet (FUV: 1160-1420 Å) spectra of 49 nearby (d ≲ 100 pc) F3-K3 main-sequence stars, located at high ecliptic latitudes (north and south), using the Cosmic Origins Spectrograph of the Hubble Space Telescope. The ecliptic poles receive higher exposures from scanning missions like the …
A Hard Look at Relativistic Reverberation in MCG-5-23-16 and SWIFT J2127.4+5654: Testing the Lamppost Model
Miller, J. M.; Zoghbi, A.; Cackett, E.
X-ray reverberation mapping has emerged as a new tool to probe accretion in active galactic nuclei (AGN), providing a potentially powerful probe of accretion at the black hole scale. The lags, along with relativistic spectral signatures are often interpreted in light of the lamppost model. Focusing specifically on testing the prediction of the rel…
The Merger Dynamics of the Galaxy Cluster A1775: New Insights from Chandra and XMM-Newton for a Cluster Simultaneously Hosting a Wide-angle Tail and a Narrow-angle Tail Radio Source
Hu, Dan; Xu, Haiguang; Zhu, Zhenghao +13 more
We present a new study of the merger dynamics of A1775 by analyzing the high-quality Chandra and XMM-Newton archival data. We confirm/identify an arc-shaped edge (i.e., the head) at ∼48 kpc west of the X-ray peak, a split cold gas tail that extends eastward to ∼163 kpc, and a plume of spiral-like X-ray excess (within about 81-324 kpc northeast of …
The origin of the soft X-ray excess in the narrow-line Seyfert 1 galaxy SBS 1353 + 564
Gu, Qiusheng; Guo, Xiaotong; Ding, Nan +2 more
We present for the first time the timing and spectral analyses for a narrow-line Seyfert 1 galaxy, SBS 1353 + 564, using XMM-Newton and Swift multiband observations from 2007 to 2019. Our main results are as follows: (1) The temporal variability of SBS 1353+564 is random, while the hardness ratio is relatively constant over a time span of 13 yr; (…