Conveners
A7: Astronomy I
- Kitiyanee Asanok (์NARIT)
A7: Astronomy I
- Thiranee Khumlumlert (Naresuan University)
Neutron monitors are instruments that can be used to study low energy cosmic rays. In addition to providing information about the fundamental properties of cosmic rays, such as how they are produced and their composition, they may be helpful for forecasting space weather. This could provide an early warning against increased radiation levels for satellites or astronauts in space from solar...
We will give a review of the THASSOS (THAi Sky Survey of oEA stars) project which is focused on the photometric and spectroscopic search for and studies of mass-accreting pulsating components of Algol-type systems (oEA stars). We will report about recent discoveries of new oEA stars obtained with NARIT's facilities and discuss the difference in the oscillation spectra of mass-accreting components.
We study the evolution of V339 Del (Nova Del 2013) during 0.37-75 days after discovery. Spectra from the Liverpool Telescope were collected and analysed to find the velocity of ejecta (v$_{ej}$), relative radiation with respect to continuum level (R$^*$$_{\lambda}$), and FWHM of the radiation. The evolution of light curve was explained by adopting an ideal nova light curve as criteria. We...
We present the 21 cm neutral hydrogen (HI) observations of 439 nearby galaxies from the Green Bank Telescope, USA. Our targets are drawn from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) program, whose sample is uniformly selected from the SDSS Data Release 13 with the stellar mass greater than 10$^9$ $M_{sun}$ and no pre-selection on galaxy type. The average redshift of...
Dark matter plays major role in the large-scale structure formation of the universe. The leading candidate for DM particle is generally called Weakly Interacting Massive Particles (WIMPs) for its properties inferred from astronomical observations. Such DM particle would only interact via weak interaction and could decay or self-annihilate into other standard model particles such as...
In this work, we present a study of regions near the Galactic plane with extreme spectral index, $\beta$ $\approx$ 8-9, which was calculated using PLANCK temperature maps for frequency bands at 143, 217 and 353 GHz. Usually, the radiation from Galactic plane regions in these frequency ranges is dominated by thermal dust emission with typical spectral index $\beta$ $\approx$ 1-2. It is rather...
To date, two exomoon candidates have been proposed but confirming their existence remains a challenging task as tools to fit light curves of exoplanets with moons are not yet available. Transit Timing Variation (TTV) and Transit Duration Variation (TDV) signals of transiting exoplanets due to the presence of moon, which have a phase difference of 90 degrees, provide a unique feature that can...
Pulsars are small, dense stars which rotate up to 1500 times per second and emit radio waves in a directed beam along their magnetic axis. Pulsars are remarkably stable rotators, and by measuring the arrival times of the radio beam the pulsar can be used as a clock in space. Applications of pulsar timing have led to the first exoplanet system, stringent tests of theories of gravity and have...
PSR J10203+0038 is a transitional millisecond pulsar (tMSP) in an eclipsing binary system, which has been observed to switch between the radio loud millisecond pulsar (MSP) and low-mass-X-ray binary (LMXB) states. This behavior offers a great opportunity to study the origin of MSPs and confirming the ‘recycling’ scenario, a theoretical model of MSP's origin. We develop an automated pipeline to...
We consider cosmological scalar field evolving under exponential potential of the Non-minimal Derivative Coupling (NMDC) gravity model in Palatini formalism. Slow-roll regime is assumed. GR and metric formalism NMDC cases are compared in this study. Phase portraits show that Palatini NMDC effect restricts acceleration phase into smaller region in the phase space. NMDC effect of the Palatini...
WASP-43b is a hot Jupiter exoplanet with an ultrashort orbital period, 0.81347 days. From previous studies, there is a possibility that the orbital period of WASP-43b is decreasing. However, from the recent studies, the results show that there is no change in the orbital period of the system. Therefore, in this work, the orbital period change of WASP-43b is investigated. Nine transit light...
An electron/positron pair halo is formed by electromagnetic cascades that initiate when the high energy gamma-rays from extragalactic sources -- i.e. Blazar AGN -- interact with the cosmic infrared background (CIB) so that are absorbed via the electron/positron pair production process. The high energy electron/positron pairs produced could up-scatter the cosmic microwave background (CMB) so...
Neutron monitors usually measure the flux of cosmic rays above a geomagnetic cutoff rigidity (momentum per charge). Recently, we have developed a new capability to also study the momentum (or energy) distribution of cosmic rays. Here we use time-delay histograms collected at the Princess Sirindhorn Neutron Monitor (PSNM), Thailand, which has the world's highest vertical cutoff rigidity for a...
Gravitational Optical Transient Observer (GOTO) is a set of telescopes primarily for optical follow-up observation of gravitational wave from projects such as LIGO and VIRGO. It can cover at least18 square degree of sky, and at most 36 square degree per pointing. The secondary objective of GOTO is to perform an all-sky survey. Each night, it could cover as much as 20,000 square degree of sky....
