SDSS J092712.64+294344.0: recoiling black hole or merging galaxies?

We report long-slit spectroscopic observations of SDSS J092712+294344 carried-out at the recently commissioned 2m telescope in IUCAA Girawali Observatory, India. This AGN-like source is known to feature three sets of emission lines at zem = 0.6972, 0.7020 and 0.7128. Different scenarios such as a recoiling black hole after asymmetric emission of gravitational waves, binary black holes and possible merging systems are proposed for this object. We test these scenarios by comparing our spectra with that from the Sloan Digital Sky Survey (SDSS), obtained 4 years prior to our observations. Comparing the redshifts of [OIII]4960,5008 we put a 3 sigma limit on the relative acceleration to be less than 32 km s^-1 yr^-1 between different emitting regions. Using the 2D spectra obtained at different position angles we show that the [OIII]5008 line from the zem = 0.7128 component is extended beyond the spectral point spread function. We infer the linear extent of this line emitting region is ~8 kpc. We also find a tentative evidence for an offset between the centroid of the [OIII]5008 line at zem = 0.7128 and the QSO trace when the slit is aligned at a position angle of 299 degrees. This corresponds to the zem = 0.7128 system being at an impact parameter of ~1 kpc with respect to the zem = 0.6972 in the north west direction. Based on our observations we conclude that the binary black hole model is most unlikely. The spatial extent and the sizes are consistent with both black hole recoil and merging scenarios.Comment: accepted for publication in MNRAS Letter

Noncommutative tensor triangulated categories and coherent frames

We develop a point-free approach for constructing the Nakano-Vashaw-Yakimov-Balmer spectrum of a noncommutative tensor triangulated category under some mild assumptions. In particular, we provide a conceptual way of classifying radical thick tensor ideals of a noncommutative tensor triangulated category using frame theoretic methods, recovering the universal support data in the process. We further show that there is a homeomorphism between the spectral space of radical thick tensor ideals of a noncommutative tensor triangulated category and the collection of open subsets of its spectrum in the Hochster dual topology

Properties of Multihomogeneous Spaces and relation with T-varieties

We study multihomogeneous spaces corresponding to ${\mathbb Z}^n$-graded algebras over an algebraically closed field of characteristic 0 and their relation with the description of $T$-varieties.Comment: 10 page

Probing the time variability of five Fe low broad absorption line quasars

We study the time variability of five Fe Low ionization Broad Absorption Line (FeLoBAL) QSOs using repeated spectroscopic observations with the 2m telescope at IUCAA Girawali observatory (IGO) spanning an interval of upto 10 years. We report a dramatic variation in Al III and Fe III fine-structure lines in the spectra of SDSS J221511.93-004549.9 (z_em ~ 1.478). However, there is no such strong variability shown by the C IV absorption. This source is known to be unusual with (i) the continuum emission dominated by Fe emission lines, (ii) Fe III absorption being stronger than Fe II and (iii) the apparent ratio of Fe III UV 48 to Fe III UV 34 absorption suggesting an inverted population ratio. This is the first reported detection of time variability in the Fe III fine-structure lines in QSO spectra. There is a strong reduction in the absorption strength of these lines between year 2000 and 2008. Using the template fitting techniques, we show that the apparent inversion of strength of UV lines could be related to the complex spectral energy distribution of this QSO. The observed variability can be related to change in the ionization state of the gas or due to transverse motion of this absorbing gas. The shortest variability timescale of Al III line gives a lower limit on the electron density of the absorbing gas as n_e >= 1.1 x 10^4 cm^-3. The remaining 4 FeLoBALs do not show any changes beyond the measurement uncertainties either in optical depth or in the velocity structure. We present the long-term photometric light curve for all of our sources. Among them only SDSS J221511.93-004549.9 shows significant (>= 0.2 mag) variability.Comment: 15 pages, 9 figures, 3 tables, Accepted for publication in MNRA

Quantum Gravity Correction to Co-bimaximal Neutrino Mixings

The quantum gravity may have strong consequence for neutrino oscillation phenemomenon. We found a significant modification of neutrino oscillation due to quantum gravity effects in specific case. We also assume that just above the electroweak scale, neutrino masses are degenerate and their mixing is co-bimaximal. Quantum gravity (Planck scale effects) leads to an effective SU(2)L × U(1) invariant dimension-5 Lagrangian involving, neutrino and Higgs fields. On symmetry breaking, this operator gives rise to correction to the neutrino masses and mixing. The gravitational interaction (MX=Mpl) demands that the element of this perturbation matrix should be independent of flavor indices. In this paper, we compute the deviation of the three neutrino mixing angles due to Planck scale effects in a co-bimaximal scheme. We found that the change in θ 12 can be as large as 3.15o &nbsp