Related papers: COSMIC : Microarcsecond resolution with a 30 metre…
We discuss interpretation of the cosmic infrared background (CIB) anisotropies detected by us recently in the Spitzer IRAC based measurements. The fluctuations are approximately isotropic on the sky consistent with their cosmological…
It has been known for more than thirty years that the distribution of molecular gas in the innermost 300 parsecs of the Milky Way, the Central Molecular Zone, is strongly asymmetric. Indeed, approximately three quarters of molecular…
We present the results of the flux density measurements at 4.85 GHz and 10.45 GHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope. The initial motivation was the need to identify the NVSS radio sources that could…
We present new WSRT observations of the micro-arcsecond quasar J1819+3845. All short term variations are attributed to interstellar scintillation of a source which is at most 30 micro-arcseconds in diameter. The timescale of the modulations…
Spectral features absorbed against some radio quasars exhibit ~50mJy variations, with the lines varying both relative to the continuum and, when several lines are present, even relative to one another. We point out that such variability can…
Recent observations of Type Ia SNe at redshifts 0 < z <1 reveal a progressive dimming which has been interpreted as evidence for a cosmological constant of Omega_Lambda ~ 0.7. An alternative explanation of the SN results is an open universe…
We have monitored the quasar 3C 273 in optical $V$, $R$ and $I$ bands from 2005 to 2016. Intraday variability (IDV) is detected on seven nights. The variability amplitudes for most of nights are less than 10\% and four nights more than…
Annual variations of interstellar scintillation can be modelled to constrain parameters of the ionized interstellar medium. If a pulsar is in a binary system, then investigating the orbital parameters is possible through analysis of the…
Using the Arcminute Microkelvin Imager (AMI) at 16 GHz and the Very Small Array (VSA) at 33 GHz to make follow-up observations of sources in the New Extragalactic WMAP Point Source Catalogue, we have investigated the flux-density…
Turbulence is ubiquitous in the interstellar medium (ISM) of the Milky Way and other spiral galaxies. The energy source for this turbulence has been much debated with many possible origins proposed. The universality of turbulence, its…
We report here a series of observations of the interstellar scintillation (ISS) of the double pulsar J0737$-$3039 over the course of 18 months. As in earlier work (Coles et al., 2005) the basic phenomenon is the variation in the ISS caused…
This paper describes some interesting properties of waves in, and oscillations of, the interstellar medium in the direction normal to the plane of the Galaxy. Our purpose is to examine possible reasons for four observed phenomena: the…
High-amplitude variability in Young Stellar Objects (YSOs) is usually associated with episodic accretion events. It has not been observed so far in massive YSOs. Here, the high-amplitude variable star sample of ContrerasPe\~{n}a et…
Recent work has revealed a 62 (+/-) 3-million-year cycle in the fossil diversity in the past 542 My, however no plausible mechanism has been found. We propose that the cycle may be caused by modulation of cosmic ray (CR) flux by the Solar…
20 months of observations of the radio emission at 15 GHz from Cygnus X-1, starting in 1996 October, show variations at the binary period of 5.6 days, but with a phase offset from those at X-ray wavelengths. There are also longer-term…
We show that, contrary to simple predictions, most AGNs show at best only a small increase of lags with increasing wavelength in the J, H, K, and L bands . We suggest that a possible cause of this near simultaneity of the variability from…
New multi-epoch, mid-infrared (8-13 microns) spectrophotometric observations are presented for 30~late-type stars. The observations were collected over a four year period (1994-1997), permitting an investigation of the mid-infrared spectral…
I use a method based on interstellar scintillations for discerning information about source sizes on scales less than one micro-arc sec. I use a comprehensive model for a pulsar signal, scintillated amplitude modulated noise, that includes…
Using three epochs of VLA observations of the Galactic Plane in the first quadrant taken ~15 years apart, we have conducted a search for a population of variable Galactic radio emitters in the flux density range 1-100 mJy at 6 cm. We find…
Radio waves are imprinted with propagation effects from ionized media through which they pass. Owing to electron density fluctuations, compact sources (pulsars, masers, and compact extragalactic sources) can display a wide variety of…