Quasinormal Modes and Thermodynamics of Linearly Charged BTZ Black holes in Massive Gravity in (Anti)de Sitter Space Time

In this work we study the Quasi Normal Modes(QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter((A)dS) space time. It is found that the behavior of QNMs changes with the massive parameter and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter and also on the charge of the black hole.Comment: Prepared for submitting to EP

Economics of production and socioeconomics of culture

Coastal cultivation of edible molluscs is an efficient method of converting marine phytoplankton into nutritious and palatable food. The economic components of different systems of culture varies considerably depending mainly on the various methods adopted in the culture systems

Technology of mussel culture

Five different teclmiques arc used in mussel culture (1) Sea bottom culture (2) Pole culture (3) Rack culture (4) Long line culture (5) Raft cultur

Fishery and biology of mussels

Two species of mussels occur in India, the green mussel, Perna viridis and the brown mussel, Perna indic

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

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