We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the center of PGC 043234 (d 90 Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of L 10 44 ergs s −1 and a total integrated energy of E 7 × 10 50 ergs radiated over the ∼ 6 months of observations presented. The UV/optical emission of the source is well-fit by a blackbody with roughly constant temperature of T ∼ 35, 000 K, while the luminosity declines by roughly a factor of 16 over this time. The optical/UV luminosity decline is broadly consistent with an exponential decline, L ∝ e −t/t0 , with t 0 60 days. ASASSN14li also exhibits soft X-ray emission comparable in luminosity to the optical and UV emission but declining at a slower rate, and the X-ray emission now dominates. Spectra of the source show broad Balmer and helium lines in emission as well as strong blue continuum emission at all epochs. We use the discoveries of ASASSN14li and ASASSN-14ae to estimate the TDE rate implied by ASAS-SN, finding an average rate of r 4.1 × 10 −5 yr −1 per galaxy with a 90% confidence interval of (2.2 − 17.0) × 10 −5 yr −1 per galaxy. ASAS-SN found roughly 1 TDE for every 70 Type Ia supernovae in 2014, a rate that is much higher than that of other surveys.

Ages and masses of young stars are often estimated by comparing their luminosities and effective temperatures to pre-main sequence stellar evolution tracks, but magnetic fields and starspots complicate both the observations and evolution. To understand their influence, we study the heavily-spotted weak-lined T-Tauri star LkCa 4 by searching for spectral signatures of radiation originating from the starspot or starspot groups. We introduce a new methodology for constraining both the starspot filling factor and the spot temperature by fitting two-temperature stellar atmosphere models constructed from Phoenix synthetic spectra to a high-resolution near-IR IGRINS spectrum. Clearly discernable spectral features arise from both a hot photospheric component T hot ∼ 4100 K and to a cool component T cool ∼ 2700 − 3000 K, which covers ∼ 80% of the visible surface. This mix of hot and cool emission is supported by analyses of the spectral energy distribution, rotational modulation of colors and of TiO band strengths, and features in low-resolution optical/near-IR spectroscopy. Although the revised effective temperature and luminosity make LkCa 4 appear much younger and lower mass than previous estimates from unspotted stellar evolution models, appropriate estimates will require the production and adoption of spotted evolutionary models. Biases from starspots likely afflict most fully convective young stars and contribute to uncertainties in ages and age spreads of open clusters. In some spectral regions starspots act as a featureless "veiling" continuum owing to high rotational broadening and heavy line-blanketing in cool star spectra. Some evidence is also found for an anti-correlation between the velocities of the warm and cool components.

We present $UBVI_c$ CCD photometry of the young open cluster Stock 8 with the aim to study the basic properties and star formation scenario in this region. The radius of the cluster is found to be $\sim 6^{\prime}$ ($\sim 3.6$ pc) and the reddening within the cluster region varies from $E(B-V)=0.40$ to 0.60 mag. The cluster is located at a distance of $2.05 \pm 0.10$ kpc. Using H$\alpha$ slitless spectroscopy and 2MASS NIR data we identified H$\alpha$ emission and NIR excess young stellar objects (YSOs), respectively. The colour-magnitude diagrams of these YSOs reveal that majority of these objects have ages between 1 to 5 Myr indicating a non-coeval star formation in the cluster. Massive stars in the cluster region reveal an average age of $\le$ 2 Myr. In the cluster region ($r \le 6^\prime$) the slope of the mass function (MF), $\Gamma$, in the mass range $\sim 1.0 \le M/M_\odot < 13.4$ can be represented by a power law having a slope of $-1.38\pm0.12$, which agrees well with Salpeter value (-1.35). In the mass range $0.3 \le M/M_\odot < 1.0$, the MF is also found to follow a power law with a shallower slope of $\Gamma = -0.58\pm 0.23$ indicating a break in the slope of the IMF at $\sim 1 M_\odot$. The slope of the $K$-band luminosity function for the cluster ($r \le 6^\prime$) is found to be $0.31\pm0.02$, which is smaller than the average value ($\sim$ 0.4) obtained for embedded star clusters. A significant number of YSOs are distributed along a Nebulous Stream towards the east side of the cluster. A small cluster is embedded in the Nebulous Stream. The YSOs lying in the Nebulous Stream and in the embedded cluster are found to be younger than the stars in the cluster Stock 8. It appears that star formation activity in the Nebulous Stream and embedded cluster may be independent from that of Stock 8.Comment: 48 pages, 29 figures, accepted for publication in MNRA

Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530-710 nm), and R = 3000 in the blue (340-560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O III] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O III] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H II regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.