Tinggui Wang - Academia.edu (original) (raw)
Papers by Tinggui Wang
We report the discovery of a possible close binary system of quasars in SDSS J1048+0055. The [OII... more We report the discovery of a possible close binary system of quasars in SDSS J1048+0055. The [OIII]λλ4959,5007 emission lines are clearly double-peaked, and two discrete radio sources with a projected physical separation of ∼ 20 pc are found in the VLBA milliarcsec resolution image at 8.4 GHz. Each of the [O III]λλ4959, 5007 doublets and Hβ can be well modelled by two Gaussians and the line ratio, [OIII]λ5007/Hβ ∼ 7, is typical of Seyfert 2 galaxies. No broad component of Hβ was detected and its [OIII]λ5007 luminosity, L[OIII] ≈ 9.2 × 10 42 erg s −1, is comparable to luminous quasars and is a few ten times more luminous than typical Seyfert galaxies. One natural interpretation is that SDSS J1048+0055 contains two close quasar-like nuclei and the BLR around them are obscured. Other possible models are also discussed. We suggest that double-peaked narrow emission line profile may be an effective way of selecting candidates of binary black holes with intermediate separation.
We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate inter... more We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate intermediate-mass black hole hosted by the dwarf galaxy SDSS J160531.84+174826.1 at z = 0.032. A broad component of the Hα line with FWHM=781km s −1 is detected in its optical spectrum, and a bright, point-like nucleus is evident from a HST imaging observation. Non-thermal X-ray emission is also detected from the nucleus. The black hole mass, as estimated from the luminosity and width of the broad Hα component, is about 7 ×10 4 M⊙. The host galaxy appears to be a disk galaxy with a boxy bulge or nuclear bar; with an absolute magnitude of MR = −17.8, it is among the least luminous host galaxies ever identified for a Seyfert 1.
PG 1411+442, and PG 0043+039. All three objects are found to be X-ray quiet, possibly due to subs... more PG 1411+442, and PG 0043+039. All three objects are found to be X-ray quiet, possibly due to substantial intrinsic absorption with N-H > 10(23) cm(-2) but might have intrinsically a more typical spectral energy distribution. This picture is supported by explicit spectral fits to the combined ROSAT/ASCA data of the nearby bright object PG 1411+442. An analysis of the large number of radio-quiet quasars not detected in the ROSAT All-Sky Survey indicates that perhaps only a small fraction of BAL quasars have not been recognized before and that the number of intrinsically X-ray quiet quasars must be small.
We have conducted a systematic investigation of the origin and underlying physics of the line--li... more We have conducted a systematic investigation of the origin and underlying physics of the line--line and line--continuum correlations of AGNs, particularly the Baldwin effect. Based on the homogeneous sample of Seyfert 1s and QSOs in the SDSS DR4, we find the origin of all the emission-line regularities is Eddington ratio (L/Ledd). The essential physics is that L/Ledd regulates the distributions of the properties (particularly column density) of the clouds bound in the line-emitting region.
Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare... more Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare optically-selected active galactic nuclei (AGNs) with control star-forming and quiescent galaxies on galactic, inter-halo and larger scales. We find that AGNs are preferentially found in two specific stages of galaxy evolution: star-burst and ‘green valley’ phases, and that the stellar population of their host galaxies is quite independent of stellar mass, different from normal galaxies. Combining galaxy-galaxy lensing and galaxy clustering on large scales, we measure the mass of AGN host halos. The typical halo mass is about 10 h−1M , similar to the characteristic mass in the stellar mass-halo mass relation (SHMR). For given stellar mass, AGN host galaxies and star-forming galaxies share the same SHMR, while quiescent galaxies have more massive halos. Clustering analysis on halo scales reveals that AGNs are surrounded by a larger number of satellites (with stellar mass down to 1/1000 o...
Astronomy & Astrophysics
Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare... more Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compared optically selected active galactic nuclei (AGNs) with control star-forming and quiescent galaxies on galactic and inter-halo scales, and larger. We find that AGNs are preferentially found in two specific stages of galaxy evolution: in the starburst and ‘green valley’ phases. We also find that the stellar population of their host galaxies is quite independent of stellar mass, which is not the case for more typical galaxies. Combining galaxy-galaxy lensing and galaxy clustering on large scales, we measured the mass of AGN host halos. The typical halo mass is about 1012 h−1 M⊙, similar to the characteristic mass in the stellar mass-halo mass relation (SHMR). For a given stellar mass, AGN host galaxies and star-forming galaxies share the same SHMR, while quiescent galaxies have more massive halos. Clustering analyses on halo scales reveals that AGNs are surrounded by a larger number of sat...
Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray
The Astrophysical Journal Supplement Series
The Astrophysical Journal
The Astrophysical Journal Letters
The Astrophysical Journal
The Astrophysical Journal
The Astrophysical Journal
The Astrophysical Journal
We analyze the X-ray, optical, and mid-infrared data of a “changing-look” Seyfert galaxy SDSS J15... more We analyze the X-ray, optical, and mid-infrared data of a “changing-look” Seyfert galaxy SDSS J155258+273728 at z ≃ 0.086. Over a period of one decade (2009–2018), its broad Hα line intensity increased by a factor of ∼4. Meanwhile, the X-ray emission in 2014 as observed by Chandra was about five times brighter than that in 2010 by Suzaku, and the corresponding emissions in the V-band, mid-infrared W1 band brighten by ∼0.18, 0.32 mag, respectively. Moreover, the absorption in X-rays is moderate and stable, i.e., N H ∼ 10 21 cm − 2 , but the X-ray spectrum becomes harder in the 2014 Chandra bright state (i.e., photon index Γ = 1.52 − 0.06 + 0.06 ) than that of the 2010 Suzaku low state ( Γ = 2.03 − 0.21 + 0.22 ). With an Eddington ratio being lower than a few percent, the inner region of the accretion disk in SDSS J155258+273728 is likely a hot accretion flow. We then compile from literature the X-ray data of “changing-look” active galactic nuclei (AGNs), and find that they generally ...
The Astrophysical Journal
The Astrophysical Journal
We report the discovery of a possible close binary system of quasars in SDSS J1048+0055. The [OII... more We report the discovery of a possible close binary system of quasars in SDSS J1048+0055. The [OIII]λλ4959,5007 emission lines are clearly double-peaked, and two discrete radio sources with a projected physical separation of ∼ 20 pc are found in the VLBA milliarcsec resolution image at 8.4 GHz. Each of the [O III]λλ4959, 5007 doublets and Hβ can be well modelled by two Gaussians and the line ratio, [OIII]λ5007/Hβ ∼ 7, is typical of Seyfert 2 galaxies. No broad component of Hβ was detected and its [OIII]λ5007 luminosity, L[OIII] ≈ 9.2 × 10 42 erg s −1, is comparable to luminous quasars and is a few ten times more luminous than typical Seyfert galaxies. One natural interpretation is that SDSS J1048+0055 contains two close quasar-like nuclei and the BLR around them are obscured. Other possible models are also discussed. We suggest that double-peaked narrow emission line profile may be an effective way of selecting candidates of binary black holes with intermediate separation.
We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate inter... more We report the discovery of a dwarf Seyfert 1 active galactic nucleus (AGN) with a candidate intermediate-mass black hole hosted by the dwarf galaxy SDSS J160531.84+174826.1 at z = 0.032. A broad component of the Hα line with FWHM=781km s −1 is detected in its optical spectrum, and a bright, point-like nucleus is evident from a HST imaging observation. Non-thermal X-ray emission is also detected from the nucleus. The black hole mass, as estimated from the luminosity and width of the broad Hα component, is about 7 ×10 4 M⊙. The host galaxy appears to be a disk galaxy with a boxy bulge or nuclear bar; with an absolute magnitude of MR = −17.8, it is among the least luminous host galaxies ever identified for a Seyfert 1.
PG 1411+442, and PG 0043+039. All three objects are found to be X-ray quiet, possibly due to subs... more PG 1411+442, and PG 0043+039. All three objects are found to be X-ray quiet, possibly due to substantial intrinsic absorption with N-H > 10(23) cm(-2) but might have intrinsically a more typical spectral energy distribution. This picture is supported by explicit spectral fits to the combined ROSAT/ASCA data of the nearby bright object PG 1411+442. An analysis of the large number of radio-quiet quasars not detected in the ROSAT All-Sky Survey indicates that perhaps only a small fraction of BAL quasars have not been recognized before and that the number of intrinsically X-ray quiet quasars must be small.
We have conducted a systematic investigation of the origin and underlying physics of the line--li... more We have conducted a systematic investigation of the origin and underlying physics of the line--line and line--continuum correlations of AGNs, particularly the Baldwin effect. Based on the homogeneous sample of Seyfert 1s and QSOs in the SDSS DR4, we find the origin of all the emission-line regularities is Eddington ratio (L/Ledd). The essential physics is that L/Ledd regulates the distributions of the properties (particularly column density) of the clouds bound in the line-emitting region.
Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare... more Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare optically-selected active galactic nuclei (AGNs) with control star-forming and quiescent galaxies on galactic, inter-halo and larger scales. We find that AGNs are preferentially found in two specific stages of galaxy evolution: star-burst and ‘green valley’ phases, and that the stellar population of their host galaxies is quite independent of stellar mass, different from normal galaxies. Combining galaxy-galaxy lensing and galaxy clustering on large scales, we measure the mass of AGN host halos. The typical halo mass is about 10 h−1M , similar to the characteristic mass in the stellar mass-halo mass relation (SHMR). For given stellar mass, AGN host galaxies and star-forming galaxies share the same SHMR, while quiescent galaxies have more massive halos. Clustering analysis on halo scales reveals that AGNs are surrounded by a larger number of satellites (with stellar mass down to 1/1000 o...
Astronomy & Astrophysics
Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compare... more Based on the spectroscopic and shear catalogs for SDSS galaxies in the local Universe, we compared optically selected active galactic nuclei (AGNs) with control star-forming and quiescent galaxies on galactic and inter-halo scales, and larger. We find that AGNs are preferentially found in two specific stages of galaxy evolution: in the starburst and ‘green valley’ phases. We also find that the stellar population of their host galaxies is quite independent of stellar mass, which is not the case for more typical galaxies. Combining galaxy-galaxy lensing and galaxy clustering on large scales, we measured the mass of AGN host halos. The typical halo mass is about 1012 h−1 M⊙, similar to the characteristic mass in the stellar mass-halo mass relation (SHMR). For a given stellar mass, AGN host galaxies and star-forming galaxies share the same SHMR, while quiescent galaxies have more massive halos. Clustering analyses on halo scales reveals that AGNs are surrounded by a larger number of sat...
Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray
The Astrophysical Journal Supplement Series
The Astrophysical Journal
The Astrophysical Journal Letters
The Astrophysical Journal
The Astrophysical Journal
The Astrophysical Journal
The Astrophysical Journal
We analyze the X-ray, optical, and mid-infrared data of a “changing-look” Seyfert galaxy SDSS J15... more We analyze the X-ray, optical, and mid-infrared data of a “changing-look” Seyfert galaxy SDSS J155258+273728 at z ≃ 0.086. Over a period of one decade (2009–2018), its broad Hα line intensity increased by a factor of ∼4. Meanwhile, the X-ray emission in 2014 as observed by Chandra was about five times brighter than that in 2010 by Suzaku, and the corresponding emissions in the V-band, mid-infrared W1 band brighten by ∼0.18, 0.32 mag, respectively. Moreover, the absorption in X-rays is moderate and stable, i.e., N H ∼ 10 21 cm − 2 , but the X-ray spectrum becomes harder in the 2014 Chandra bright state (i.e., photon index Γ = 1.52 − 0.06 + 0.06 ) than that of the 2010 Suzaku low state ( Γ = 2.03 − 0.21 + 0.22 ). With an Eddington ratio being lower than a few percent, the inner region of the accretion disk in SDSS J155258+273728 is likely a hot accretion flow. We then compile from literature the X-ray data of “changing-look” active galactic nuclei (AGNs), and find that they generally ...
The Astrophysical Journal
The Astrophysical Journal