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PRECISE PHOTOMETRIC TRANSIT FOLLOW-UP OBSERVATIONS of FIVE CLOSE-IN EXOPLANETS : UPDATE on THEIR PHYSICAL PROPERTIES Aritra Chakrabarty†1, 2 and Sujan Sengupta‡1
Draft version May 28, 2019 Typeset using LATEX default style in AASTeX62 PRECISE PHOTOMETRIC TRANSIT FOLLOW-UP OBSERVATIONS OF FIVE CLOSE-IN EXOPLANETS : UPDATE ON THEIR PHYSICAL PROPERTIES Aritra Chakrabartyy1, 2 and Sujan Senguptaz1 1Indian Institute of Astrophysics, Koramangala 2nd Block, Bangalore 560034, India 2University of Calcutta, Salt Lake City, JD-2, Kolkata 750098, India (Accepted for publication in the Astronomical Journal) ABSTRACT We report the results of the high precision photometric follow-up observations of five transiting hot jupiters - WASP-33b, WASP-50b, WASP-12b, HATS-18b and HAT-P-36b. The observations are made from the 2m Himalayan Chandra Telescope at Indian Astronomical Observatory, Hanle and the 1.3m J. C. Bhattacharyya Telescope at Vainu Bappu Observatory, Kavalur. This exercise is a part of the capability testing of the two telescopes and their back-end instruments. Leveraging the large aperture of both the telescopes used, the images taken during several nights were used to produce the transit light curves with high photometric S/N (> 200) by performing differential photometry. In order to reduce the fluctuations in the transit light curves due to various sources such as stellar activity, varying sky transparency etc. we preprocessed them using wavelet denoising and applied Gaussian process correlated noise modeling technique while modeling the transit light curves. To demonstrate the efficiency of the wavelet denoising process we have also included the results without the denoising process. A state-of-the-art algorithm used for modeling the transit light curves provided the physical parameters of the planets with more precise values than reported earlier. -
Indian Institute of Astrophysics
Indian Institute of Astrophysics The Indian Institute of Astrophysics (IIA), an autonomous research institute funded by the Department of Science & Technology, is devoted to research in Astronomy & Astrophysics, and the Related Physics and Instrumentation. IIA has a rich history of over two centuries and has to its credit some important discoveries such as those of the Evershed effect, atmosphere on Jupiter's satellite Ganymede, the rings around Uranus and the asteroid Ramanujan. Research Programmes Research fields in Astronomy & Astrophysics at IIA range from the studies of the nearby sun and solar system objects to the distant galaxies, quasars and gamma-ray burst sources. Sun and the Solar System - Solar activity - sunspots, prominences; Solar Chromosphere and Corona; Comets; Solar Terrestrial relationships Stellar Physics - Formation and Evolution of Stars; Comet Machholz Planetary Nebulae; Stellar Atmospheres; Star observed from VBO Clusters; Stellar Variability; Novae; Supernovae; Brown Dwarfs, Pulsars Solar Corona Extragalactic Astronomy - Star formation in galaxies; Activity in Galaxies; Groups and Clusters of Galaxies; Gamma-ray burst events Theoretical Astrophysics and Related Physics - Magnetohydrodynamic and Radiative Processes in Astrophysical Objects; Structure of Neutron Stars; Blackhole Physics; Structure and Dynamics of Galaxies and Star Clusters; General Theory of Relativity; Cosmology; Astroparticle Physics; Atomic and Molecular Physics NGC 925 observed with the 2m HCT Instrumentation - UV Imaging Telescope for the Indian Astronomy Satellite (ASTROSAT); back-end instruments for the various observing facilities. Facilities The Institute's research activities are supported by excellent facilities at its headquarters in Bangalore and its field stations at Kodaikanal, Kavalur, Gauribidanur, Hosakote and Hanle. The Solar Observatory: located at Kodaikanal consists of a Tower Tunnel Telescope, Spectroheliographs and Ionosondes. -
GW190814: Gravitational Waves from the Coalescence of a 23 M Black Hole 4 with a 2.6 M Compact Object
1 Draft version May 21, 2020 2 Typeset using LATEX twocolumn style in AASTeX63 3 GW190814: Gravitational Waves from the Coalescence of a 23 M Black Hole 4 with a 2.6 M Compact Object 5 LIGO Scientific Collaboration and Virgo Collaboration 6 7 (Dated: May 21, 2020) 8 ABSTRACT 9 We report the observation of a compact binary coalescence involving a 22.2 { 24.3 M black hole and 10 a compact object with a mass of 2.50 { 2.67 M (all measurements quoted at the 90% credible level). 11 The gravitational-wave signal, GW190814, was observed during LIGO's and Virgo's third observing 12 run on August 14, 2019 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector 2 +41 13 network. The source was localized to 18.5 deg at a distance of 241−45 Mpc; no electromagnetic 14 counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured +0:008 15 with gravitational waves, 0:112−0:009, and its secondary component is either the lightest black hole 16 or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless 17 spin of the primary black hole is tightly constrained to 0:07. Tests of general relativity reveal no ≤ 18 measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at −3 −1 19 high confidence. We estimate a merger rate density of 1{23 Gpc yr for the new class of binary 20 coalescence sources that GW190814 represents. -
Indian Institute of Astrophysics Bangalore 560034
Indian Institute of Astrophysics Bangalore 560034 The Indian Institute of Astrophysics (IIA) traces its origin to relativity, cosmology, astroparticle physics, atomic and a small private observatory set up during 1786 at Madras molecular physics. (Chennai), which led to the establishment of the Solar Observatory in 1899 at Kodaikanal. In 1971, the Facilities: Kodaikanal Observatory was made into an autonomous institution under the Department of Science & Technology, Kodaikanal Observatory: This Observatory has been the Government of India. With a rich history of over 200 years, principal center of activity in observational solar physics, IIA is a premier institute in the country devoted to basic for over a century. At present, the main facility is the solar research, instrumentation and training in astronomy, tunnel telescope fitted with a spectrograph, which is in astrophysics and related physical sciences. regular use since 1962; a spectro-polarimeter has also been added. This observatory has a unique collection of the Sun’s photographic images archived over the last hundred years. These images are now being digitized to study the finer details of the Sun, Sun-weather pattern etc. Daily observations of the solar photosphere and chromosphere are being obtained as a part of the synoptic study. It was in this Observatory, John Evershed discovered the radial motion in sunspots, now known as the Evershed effect, in 1909. The Indian Institute of Astrophysics, Bangalore. Research Programmes: Sun and the Solar System - Solar activity, sunspots, prominences, solar chromosphere, comets, asteroids, eclipse observations, radio observations of the solar corona. Stellar Physics - Formation and evolution of stars, chemical abundance of elements, planetary nebulae, planetary rings, The solar tunnel telescope at the Kodaikanal observatory. -
Prime Focus (09-10)
Highlights of the September Sky. - - - 1st - - - Last Quarter Moon Prime Focus Dusk: Venus, Spica, and Mars nearly form a straight A Publication of the Kalamazoo Astronomical Society line less than 5º long. - - - 4th — 5th - - - September 2010 Dusk: Mars is just 2º upper right of Spica, which is about 4º right of Venus. - - - 8th - - - ThisThis MonthsMonths KAS EventsEvents New Moon - - - 10th - - - Dusk: Mars is above the Observing Session: Saturday, September 4 @ 8:00 pm thin crescent Moon. Jupiter & Open Clusters - Kalamazoo Nature Center - - - 11th - - - Dusk: Venus is 6º right of General Meeting: Friday, September 10 @ 7:00 pm the Moon. Kalamazoo Area Math & Science Center - See Page 8 for Details - - - 13th - - - PM: Antares is 4º left of the Waxing Gibbous Moon. Kiwanis Star Party: Saturday, September 11 @ 8:00 pm - - - 15th - - - Kiwanis Youth Conservation Area - See Page 7 for Details First Quarter Moon thth th Observing Session: Saturday, September 18 @ 8:00 pm - - - 17 — 19 - - - PM: Jupiter and Uranus Moon, Jupiter, Uranus & Neptune- Kalamazoo Nature Center are just 0.8º apart. - - - 19thth - - - AM: Mercury at greatest western elongation (18º). InsideInside thethe Newsletter.Newsletter. .. .. - - - 21st - - - PM: Jupiter and Uranus are both at opposition Perseid Potluck Picnic Report............. p. 2 - - - 22nd - - - Board Meeting Minutes......................... p. 2 PM: Jupiter (and Uranus) are about 6º below the Night Sky Volunteer Program............. p. 3 Moon. Autumnal Equinox Jack Horkheimer..................................... p. 4 (11:09 pm EDT) NASA Space Place.................................. p. 5 - - - 23rd - - - Full Moon September Night Sky............................. p. 6 - - - 27th - - - PM: Pleiades are about 2º KAS Officers & Announcements........ p. 7 left of the Moon. General Meeting Preview.................... -
Probing the Nuclear Equation of State from the Existence of a 2.6 M Neutron Star: the GW190814 Puzzle
S S symmetry Article Probing the Nuclear Equation of State from the Existence of a ∼2.6 M Neutron Star: The GW190814 Puzzle Alkiviadis Kanakis-Pegios †,‡ , Polychronis S. Koliogiannis ∗,†,‡ and Charalampos C. Moustakidis †,‡ Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [email protected] (A.K.P.); [email protected] (C.C.M.) * Correspondence: [email protected] † Current address: Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. ‡ These authors contributed equally to this work. Abstract: On 14 August 2019, the LIGO/Virgo collaboration observed a compact object with mass +0.08 2.59 0.09 M , as a component of a system where the main companion was a black hole with mass ∼ − 23 M . A scientific debate initiated concerning the identification of the low mass component, as ∼ it falls into the neutron star–black hole mass gap. The understanding of the nature of GW190814 event will offer rich information concerning open issues, the speed of sound and the possible phase transition into other degrees of freedom. In the present work, we made an effort to probe the nuclear equation of state along with the GW190814 event. Firstly, we examine possible constraints on the nuclear equation of state inferred from the consideration that the low mass companion is a slow or rapidly rotating neutron star. In this case, the role of the upper bounds on the speed of sound is revealed, in connection with the dense nuclear matter properties. Secondly, we systematically study the tidal deformability of a possible high mass candidate existing as an individual star or as a component one in a binary neutron star system. -
The Turbulent Tale of a Tiny Galaxy by Trudy Bell and Dr
Space Place Partners’ Article August 2010 The Turbulent Tale of a Tiny Galaxy by Trudy Bell and Dr. Tony Phillips Next time you hike in the woods, pause at a babbling stream. Watch carefully how the water flows around rocks. After piling up in curved waves on the upstream side, like the bow wave in front of a motorboat, the water speeds around the rock, spilling into a riotous, turbulent wake downstream. Lightweight leaves or grass blades can get trapped in the wake, swirling round and round in little eddy currents that collect debris. Astronomers have found something similar happening in the turbulent wake of a tiny galaxy that is plunging into a cluster of 1,500 galaxies in the constellation Virgo. In this case, however, instead of collecting grass and leaves, eddy currents in the little galaxy’s tail seem to be gathering gaseous material to make new stars. “It’s a fascinating case of turbulence [rather than gravity] trapping the gas, allowing it to become dense enough to form stars,” says Janice A. Hester of the California Institute of Technology in Pasadena. The tell-tale galaxy, designated IC 3418, is only a hundredth the size of the Milky Way and hardly stands out in visible light images of the busy Virgo Cluster. Astronomers realized it was interesting, however, when they looked at it using NASA's Galaxy Evolution Explorer satellite. “Ultraviolet images from the Galaxy Evolution Explorer revealed a long tail filled with clusters of massive, young stars,” explains Hester. Galaxies with spectacular tails have been seen before. -
New Type of Black Hole Detected in Massive Collision That Sent Gravitational Waves with a 'Bang'
New type of black hole detected in massive collision that sent gravitational waves with a 'bang' By Ashley Strickland, CNN Updated 1200 GMT (2000 HKT) September 2, 2020 <img alt="Galaxy NGC 4485 collided with its larger galactic neighbor NGC 4490 millions of years ago, leading to the creation of new stars seen in the right side of the image." class="media__image" src="//cdn.cnn.com/cnnnext/dam/assets/190516104725-ngc-4485-nasa-super-169.jpg"> Photos: Wonders of the universe Galaxy NGC 4485 collided with its larger galactic neighbor NGC 4490 millions of years ago, leading to the creation of new stars seen in the right side of the image. Hide Caption 98 of 195 <img alt="Astronomers developed a mosaic of the distant universe, called the Hubble Legacy Field, that documents 16 years of observations from the Hubble Space Telescope. The image contains 200,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the Big Bang. " class="media__image" src="//cdn.cnn.com/cnnnext/dam/assets/190502151952-0502-wonders-of-the-universe-super-169.jpg"> Photos: Wonders of the universe Astronomers developed a mosaic of the distant universe, called the Hubble Legacy Field, that documents 16 years of observations from the Hubble Space Telescope. The image contains 200,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the Big Bang. Hide Caption 99 of 195 <img alt="A ground-based telescope&amp;#39;s view of the Large Magellanic Cloud, a neighboring galaxy of our Milky Way. -
Transformation of a Virgo Cluster Dwarf Irregular Galaxy by Ram Pressure Stripping: Ic3418 and Its Fireballs
The Astrophysical Journal, 780:119 (20pp), 2014 January 10 doi:10.1088/0004-637X/780/2/119 C 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A. TRANSFORMATION OF A VIRGO CLUSTER DWARF IRREGULAR GALAXY BY RAM PRESSURE STRIPPING: IC3418 AND ITS FIREBALLS Jeffrey D. P. Kenney1, Marla Geha1, Pavel Jachym´ 1,2,HughH.Crowl3, William Dague1, Aeree Chung4, Jacqueline van Gorkom5, and Bernd Vollmer6 1 Yale University Astronomy Department, P.O. Box 208101, New Haven, CT 06520-8101, USA; [email protected] 2 Astronomical Institute, Academy of Science of the Czech Republic, Bocni II 1401, 141 00 Prague, Czech Republic 3 Bennington College, Bennington, VT, USA 4 Department of Astronomy and Yonsei University Observatory, Yonsei University, 120-749 Seoul, Korea 5 Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027, USA 6 CDS, Observatoire astronomique de Strasbourg, UMR7550, 11 rue de l’universite,´ F-67000 Strasbourg, France Received 2013 August 1; accepted 2013 November 18; published 2013 December 16 ABSTRACT We present optical imaging and spectroscopy and H i imaging of the Virgo Cluster galaxy IC 3418, which is likely a “smoking gun” example of the transformation of a dwarf irregular into a dwarf elliptical galaxy by ram pressure stripping. IC 3418 has a spectacular 17 kpc length UV-bright tail comprised of knots, head–tail, and linear stellar features. The only Hα emission arises from a few H ii regions in the tail, the brightest of which are at the heads of head–tail UV sources whose tails point toward the galaxy (“fireballs”). -
Arxiv:1505.04244V1 [Astro-Ph.IM] 16 May 2015 .Srinivasulu G
Bull. Astr. Soc. India (2014) 42, 1–19 A new three-band, two beam astronomical photo-polarimeter 1 2 1 3 G. Srinivasulu ∗, A. V. Raveendran , S. Muneer †, M. V. Mekkaden , N. Jayavel4, M. R. Somashekar1, K. Sagayanathan1, S. Ramamoorthy1, 5 6 M. J. Rosario and K. Jayakumar ‡ 1Indian Institute of Astrophysics, Bangalore 560034, India 2399, "Shravanam", 2nd Block, 9th Phase, J P Nagar, Bangalore 560108, India 3No 82, 17E Main, 6th Block, Koramangala, Bangalore 560095, India 4No 22, Bandappa lane, New Byappanahalli, Bangalore 560038, India 5210, 4th Main, Lakshmi Nagar Extn, Porur, Chennai 600116, India 624, Postal Nagar, Ampuram, Vellore-632009, India Received 2014 July 23; revised ; accepted Abstract. We designed and built a new astronomical photo-polarimeter that can meas- ure linear polarization simultaneously in three spectral bands. It has a Calcite beam- displacement prism as the analyzer. The ordinary and extra-ordinary emerging beams in each spectral bands are quasi-simultaneously detected by the same photomultiplier by using a high speed rotating chopper. A rotating superachromatic Pancharatnam halfwave plate is used to modulate the light incident on the analyzer. The spectral bands are isolated using appropriate dichroic and glass filters. We show that the reduction of 50% in the efficiency of the polarimeter because of the fact that the intensities of the two beams are measured alternately is partly com- pensated by the reduced time to be spent on the observation of the sky background. The use of a beam-displacement prism as the analyzer completely removes the polar- ization of backgroundskylight, which is a major source of error during moonlit nights, especially, in the case of faint stars. -
Multi-Band Observations of Gamma Ray Bursts
J. Astrophys. Astr. (2002) 23, 123–127 Multi-band Observations of Gamma Ray Bursts S. G. Bhargavi Indian Institute of Astrophysics, Bangalore 560 034, India email: [email protected] Abstract. This talk focuses on the various aspects we learnt from multi- band observations of GRBs both, before and during the afterglow era. A statistical analysis to estimate the probable redshifts of host galaxies using the luminosity function of GRBs compatible with both the afterglow redshift data as well as the overall population of GRBs is discussed. We then address the question whether the observed fields of GRBs with precise localizations from third Inter-Planetary Network (IPN3) contain suitable candidates for their host galaxies. Key words. Gamma rays: bursts—CCD: observations—Methods: statistical. 1. Studies before the afterglow era In 1994–95 we undertook a program to carry out an optical survey of a few GRB fields chosen from the IPN3 catalog (Hurley 1995, private communication; Laros et al. 1998; Hurley et al. 2000). Deep CCD imaging of these fields was carried out at the 2.34 m and 1.02 m telescopes of Vainu Bappu Observatory (VBO), Kavalur until 1998. It was an attempt to identify the transient/quiescent counterparts of GRBs on the basis of photometric studies. For details on observations and photometric data analysis see Bhargavi (2001). In similar investigations the observers either looked for peculiar objects (Vrba et al. 1995) or an over-abundance of certain class of objects (Larson 1997) in their deep imaging surveys of IPN GRBs. None of our efforts led to an identification of a GRB counterpart. -
Tracking Star Formation in Dwarf Cluster Galaxies Cody Millard Rude
University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects January 2015 Tracking Star Formation In Dwarf Cluster Galaxies Cody Millard Rude Follow this and additional works at: https://commons.und.edu/theses Recommended Citation Rude, Cody Millard, "Tracking Star Formation In Dwarf Cluster Galaxies" (2015). Theses and Dissertations. 1829. https://commons.und.edu/theses/1829 This Dissertation is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. TRACKING STAR FORMATION IN DWARF CLUSTER GALAXIES by Cody Millard Rude Bachelor of Science, University of University of Minnesota Duluth, 2009 A Dissertation Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Doctor of Philosophy Grand Forks, North Dakota August 2015 PERMISSION Title Tracking Star Formation in Dwarf Cluster Galaxies Department Physics and Astrophysics Degree Doctor of Philosophy In presenting this dissertation in partial fulfillment of the requirements for a graduate degree from the University of North Dakota, I agree that the library of this University shall make it freely available for inspection. I further agree that permission for extensive copying for scholarly purposes may be granted by the professor who supervised my dissertation work or, in their absence, by the chairperson of the department or the dean of the School of Graduate Studies. It is understood that any copying or publication or other use of this dissertation or part thereof for financial gain shall not be allowed without my written permission.