We report an identification of SDSS J141324+530527.0 (SBS 1411+533) at z = 0.456344 as a new “changing-look” quasar with a “turn-on” spectral type transition from Type-1.9/2 to Type-1 within a rest-frame timescale of 1–10 yr by a comparison of our new spectroscopic observation and the Sloan Digital Sky Survey (SDSS) archive database. The SDSS DR7 spectrum taken in 2003 is dominated by a starlight emission from host galaxy redward of the Balmer limit, and has a non-detectable broad Hβ line. The new spectrum taken by us on 2017 June 1 and the SDSS DR14 spectrum taken on 2017 May 29 indicate that the object has a typical quasar spectrum with a blue continuum and strong Balmer broad emission lines. In addition, an intermediate spectral type can be identified in the SDSS DR13 spectrum taken in 2015. The invariability of the line wing of Mg ii λ2800 emission and timescale argument (the invariability of [O iii]λ5007 line blue asymmetry) suggests that a variation of obscuration (an accelerating outflow) is not a favorable scenario. The timescale argument allows us to believe the type transition is possibly caused by either a viscous radial inflow or a disk instability around a black hole.

We here report a spectroscopic monitor for the supernova (SN) SN 2017iuk associated with the long-duration low-luminosity gamma-ray burst (GRB) GRB 171205A at a redshift of 0.037, which is up to now the third GRB–SN event away from us. Our spectroscopic observations and spectral analysis allow us to identify SN 2017iuk as a typical broad-line Type Ic SN. A comparison study suggests that the Type IcBL SN 2017iuk resembles SN 2006aj in the following aspects: (1) similar spectra at the nearby epochs, (2) comparable evolution of the photospheric velocity obtained from the measurements based on both the Si ii λ6355 line and spectral modeling, and (3) comparable explosion parameters. This analogy could imply the formation of a neutron star in the core collapse of GRB 171205A/SN 2017iuk as previously suggested in GRB 060218/SN 2006aj. The properties of the host galaxy are discussed, which suggest that GRB 171205A/SN 2017iuk occurred in an early-type (S0), high-mass, star-forming galaxy with low specific star formation rate and solar metallicity.

We report a spectroscopic identification of two new changing-look active galactic nuclei (CL-AGNs): SDSS J104705.16+544405.8 and SDSS J120447.91+170256.8, both with a “turn-off” type transition from type-1 to type-1.8/1.9. The identification is arrived at through a follow-up spectroscopic observation of the five CL-AGNs candidates that are extracted from the sample recently released in Macleod et al. The candidates are extracted by the authors from the Sloan Digit Sky Survey Data Release 7, and are spectroscopically confirmed quasars with large amplitude variability. By compiling a sample of 26 previously identified CL-AGNs, we confirm the claim by Macleod et al. that CL-AGNs tend to be biased against a low Eddington ratio, and identify an overlap between the CL-AGNs at their dim state and the so-called intermediate-type AGNs. The overlap implies that there two populations of the intermediate-type AGNs with different origins. One is due to the torus orientation effect, and the other to the intrinsic change of the accretion rate of the central supermassive black holes.

The flare-associated stellar coronal mass ejections (CMEs) of solar-like and late-type stars profoundly impact the habitability of any expolanets in the systems. In this paper, we report the detection of flare-associated CMEs for two M-dwarfs, thanks to a high-cadence survey carried out by the Ground Wide-angle Camera system and fast photometric and spectroscopic follow-ups. The flare energies in the R band are determined to be 1.6 × 10³⁵ erg and 8.1 × 10³³ erg based on modeling of their light curves. The time-resolved spectroscopic observations start at about 20 and 40 minutes after the trigger in both cases. The large projected maximum velocity of ∼500–700 km s⁻¹ suggests that the high-velocity wings of their Hα emission lines most likely result from CME events in both stars, after excluding the possibility of chromospheric evaporation and coronal rain. The masses of the CMEs are estimated to be 1.5–4.5 × 10¹⁹ g and 7.1 × 10¹⁸ g.

We perform a systematic study of outflow in the narrow-line region (NLR) of active galactic nuclei (AGNs) at z ∼ 0.4–0.8 based upon a large sample of ∼900 quasars at z ∼ 0.4–0.8. The sample is extracted from the Sloan Digital Sky Survey by mainly requiring that (1) the g-band magnitude is brighter than 19 mag and (2) the [O iii]λ5007 emission line has a signal-to-noise ratio larger than 30. Profiles of multiple emission lines are modeled by a sum of several Gaussian functions. The spectral analysis allows us to identify (1) a prevalence of both [O iii]λ5007 line blue asymmetry and bulk velocity blueshift of both [Ne iii]λ3869 and [Ne iii]λ3426 lines, when the [O ii]λ3727 line is used as a reference. The velocity offset of the [O iii]λ5007 line is, however, distributed around a value of zero, except for a few outliers. (2) Not only the significant [O iii]λ5007 line asymmetry, but also the large bulk velocity offsets of [Ne iii]λ3869 and [Ne v]λ3426 emission lines tend to occur in the objects with high L/L _Edd, which is considerably consistent with the conclusions based on local AGNs. With three M _BH estimation methods, the significance level of the trend is found to be better than 2.9σ, 3.2σ, and 1.8σ for [O iii], [Ne iii], and [Ne v], respectively. After excluding the role of radio jets, the revealed dependence of NLR gas outflow on L/L _Edd allows us to argue that the pressure caused by the wind/radiation launched/emitted from a central supermassive black hole is the most likely origin of the outflow in these distant quasars, which implies that the outflow in luminous AGNs up to z ∼ 1 have the same origin.

The nature of the rare “Changing-look” (CL) phenomenon in active galactic nuclei (AGNs) is still under debate. We present Swift/XRT and UVOT follow-up observations of UGC 3223, a newly discovered repeat CL-AGN with type transitions of S1.5 → S2 → S1.8 occurring in a period of about 30 yr. By comparing the values previously reported in the ROSAT All-sky Survey and in the second Swift-XRT Point Source catalog, we clearly find that the X-ray flux tightly follows the optical spectral transition, in which a spectral type closer to a Seyfert 1 type is associated with a higher X-ray flux. An invariable X-ray spectral shape is, however, found in the CL phenomenon of the object. An extremely low Eddington ratio of ∼2 × 10⁻⁴ can be obtained from the X-ray luminosity for its Seyfert 2 state, which suggests the disk-wind broad-line region model best explains the CL phenomenon. A variation of the total UV emission is not revealed when compared to the previous Galaxy Evolution Explorer NUV observation, since the UVOT images indicate that ∼90% UV emission comes from intensive star formation in the host galaxy.