Search for Transiting Exoplanets with HATNet

AbstractHATNet is a network of six identical, fully automated wide field telescopes, four of which are located in Arizona, and two at Hawaii. The purpose of the network is to search for transiting extrasolar planets around relatively bright stars (8 <I< 12). The longitudinal coverage of 3.5 hours greatly enhances transit detection efficiency. HATNet has been operational since 2004, and has taken more than 1/2 million science frames at 5-min integrations, covering about 7% of the sky. Photometric precision reaches 3mmag rms at 5.5 min cadence atI≈ 8, and is 1% atI≈ 11.3. Hundreds of transitcandidateshave been detected in the data, and have been subject to vigorous follow-up by various 1m-class facilities, both spectroscopy and follow-up photometry. A fraction of the candidates that have survived these steps as not being false alarms have been observed by high resolution and precision spectrographs (primarily Keck/HIRES), to confirm their planetary nature and characterize their properties. So far nine transiting planets have been reported, making HATNet a very successful survey.

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Extrasolar planet detections with gravitational microlensing

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308016311 ◽

2007 ◽

Vol 3 (S249) ◽

pp. 25-30

Author(s):

Shude Mao ◽

Eamonn Kerins ◽

Nicholas J. Rattenbury

Keyword(s):

Light Curve ◽

Real Time ◽

Extrasolar Planets ◽

Light Curves ◽

Extrasolar Planet ◽

Galactic Centre ◽

Wide Field ◽

High Magnification ◽

Gravitational Microlensing

AbstractMicrolensing light curves due to single stars are symmetric and typically last for a month. So far about 4000 microlensing events have been discovered in real-time, the vast majority toward the Galactic centre. The presence of planets around the primary lenses induces deviations in the usual light curve which lasts from hours (for an Earth-mass [M⊕] planet) to days (for a Jupiter-mass [Mj] planet). Currently the survey teams, OGLE and MOA, discover and announce microlensing events in real-time, and follow-up teams (together with the survey teams) monitor selected events intensively (usually with high magnification) in order to identify anomalies caused by planets. So far four extrasolar planets have been discovered using the microlensing technique, with half a dozen new planet candidates identified in 2007 (yet to be published). Future possibilities include a network of wide-field 2m-class telescopes from the ground (which can combine survey and follow-up in the same setup) and a 1m-class survey telescope from space.

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A search for transiting planets in the Galactic Plane

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308026604 ◽

2008 ◽

Vol 4 (S253) ◽

pp. 343-345

Author(s):

Veronica R. Miller ◽

Michael D. Albrow

Keyword(s):

Extrasolar Planets ◽

Galactic Plane ◽

Wide Field ◽

Transiting Planets ◽

Deep Survey ◽

Initial Results

AbstractWe are carrying out a deep survey for transiting extrasolar planets in a 1 square degree field in the Galactic Plane. The images to date were taken using the Wide Field Imager on the ESO 2.2m telescope at La Silla. We present details of the analysis and initial results from the survey.

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KELT: A Wide-Field Survey of Bright Stars for Transiting Planets

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308026628 ◽

2008 ◽

Vol 4 (S253) ◽

pp. 350-353

Author(s):

Robert J. Siverd ◽

Joshua Pepper ◽

Kris Stanek ◽

Richard W. Pogge ◽

B. Scott Gaudi ◽

...

Keyword(s):

Data Reduction ◽

Field Survey ◽

Candidate Selection ◽

Wide Field ◽

Present Survey ◽

Transiting Planets ◽

The Past ◽

Initial Results ◽

Sufficient Precision

AbstractThe Kilodegree Extremely Little Telescope (KELT) is a wide-field (26° × 26°) robotic survey telescope currently operating in Sonoita, Arizona. Assembled from commercial and off-the-shelf devices, KELT currently surveys ~40% of the Northern sky with sufficient precision to detect transiting planets around bright (8 < V < 12) stars. In the past several years of operation, over 30,000 science images have been acquired. Planet candidate selection and follow-up are currently underway. A brief overview of past and present survey operations, the data reduction pipeline, and initial results follows below.

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Two temperate sub-Neptunes transiting the star EPIC 212737443

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1641 ◽

2019 ◽

Vol 488 (1) ◽

pp. 536-546

Author(s):

Mahesh Herath ◽

Tobias C Hinse ◽

John H Livingston ◽

Jesús Hernández ◽

Daniel F Evans ◽

...

Keyword(s):

High Resolution ◽

Planetary System ◽

Equilibrium Temperature ◽

Outer Planet ◽

High Resolution Imaging ◽

Transiting Planets ◽

Resolution Imaging ◽

Orbital Periods ◽

Imaging And Spectroscopy

ABSTRACT We report the validation of a new planetary system around the K3 star EPIC 212737443 using a combination of K2 photometry, follow-up high-resolution imaging and spectroscopy. The system consists of two sub-Neptune sized transiting planets with radii of 2.6R⊕ and 2.7R⊕, with orbital periods of 13.6 and 65.5 d, equilibrium temperatures of 536 and 316 K, respectively. In the context of validated K2 systems, the outer planet has the longest precisely measured orbital period, as well as the lowest equilibrium temperature for a planet orbiting a star of spectral type earlier than M. The two planets in this system have a mutual Hill radius of ΔRH = 36, larger than most other known transiting multiplanet systems, suggesting the existence of another (possibly non-transiting) planet, or that the system is not maximally packed.

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Venus: key to understanding the evolution of terrestrial planets

Experimental Astronomy ◽

10.1007/s10686-021-09766-0 ◽

2021 ◽

Author(s):

Colin F. Wilson ◽

Thomas Widemann ◽

Richard Ghail

Keyword(s):

High Temperature ◽

High Resolution ◽

Radar Imaging ◽

Space Science ◽

Interior Surface ◽

Extended Surface ◽

Earth Like Planets ◽

Orbital Mission

AbstractIn this paper, originally submitted in answer to ESA’s “Voyage 2050” call to shape the agency’s space science missions in the 2035–2050 timeframe, we emphasize the importance of a Venus exploration programme for the wider goal of understanding the diversity and evolution of habitable planets. Comparing the interior, surface, and atmosphere evolution of Earth, Mars, and Venus is essential to understanding what processes determined habitability of our own planet and Earth-like planets everywhere. This is particularly true in an era where we expect thousands, and then millions, of terrestrial exoplanets to be discovered. Earth and Mars have already dedicated exploration programmes, but our understanding of Venus, particularly of its geology and its history, lags behind. Multiple exploration vehicles will be needed to characterize Venus’ richly varied interior, surface, atmosphere and magnetosphere environments. Between now and 2050 we recommend that ESA launch at least two M-class missions to Venus (in order of priority): a geophysics-focussed orbiter (the currently proposed M5 EnVision orbiter – [1] – or equivalent); and an in situ atmospheric mission (such as the M3 EVE balloon mission – [2]). An in situ and orbital mission could be combined in a single L-class mission, as was argued in responses to the call for L2/L3 themes [3–5]. After these two missions, further priorities include a surface lander demonstrating the high-temperature technologies needed for extended surface missions; and/or a further orbiter with follow-up high-resolution surface radar imaging, and atmospheric and/or ionospheric investigations.

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Processing GOTO data with the Rubin Observatory LSST Science Pipelines I: Production of coadded frames

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2020.45 ◽

2021 ◽

Vol 38 ◽

Author(s):

J. R. Mullaney ◽

L. Makrygianni ◽

V. Dhillon ◽

S. Littlefair ◽

K. Ackley ◽

...

Keyword(s):

Gravitational Wave ◽

Time Domain ◽

Wide Area ◽

Wide Field ◽

Process Data ◽

Data Production ◽

The Time Domain ◽

Further Development ◽

High Cadence

Abstract The past few decades have seen the burgeoning of wide-field, high-cadence surveys, the most formidable of which will be the Legacy Survey of Space and Time (LSST) to be conducted by the Vera C. Rubin Observatory. So new is the field of systematic time-domain survey astronomy; however, that major scientific insights will continue to be obtained using smaller, more flexible systems than the LSST. One such example is the Gravitational-wave Optical Transient Observer (GOTO) whose primary science objective is the optical follow-up of gravitational wave events. The amount and rate of data production by GOTO and other wide-area, high-cadence surveys presents a significant challenge to data processing pipelines which need to operate in near-real time to fully exploit the time domain. In this study, we adapt the Rubin Observatory LSST Science Pipelines to process GOTO data, thereby exploring the feasibility of using this ‘off-the-shelf’ pipeline to process data from other wide-area, high-cadence surveys. In this paper, we describe how we use the LSST Science Pipelines to process raw GOTO frames to ultimately produce calibrated coadded images and photometric source catalogues. After comparing the measured astrometry and photometry to those of matched sources from PanSTARRS DR1, we find that measured source positions are typically accurate to subpixel levels, and that measured L-band photometries are accurate to $\sim50$ mmag at $m_L\sim16$ and $\sim200$ mmag at $m_L\sim18$ . These values compare favourably to those obtained using GOTO’s primary, in-house pipeline, gotophoto, in spite of both pipelines having undergone further development and improvement beyond the implementations used in this study. Finally, we release a generic ‘obs package’ that others can build upon, should they wish to use the LSST Science Pipelines to process data from other facilities.

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A Modified FlowDroid Based on Chi-Square Test of Permissions

Entropy ◽

10.3390/e23020174 ◽

2021 ◽

Vol 23 (2) ◽

pp. 174

Author(s):

Hongzhaoning Kang ◽

Gang Liu ◽

Zhengping Wu ◽

Yumin Tian ◽

Lizhi Zhang

Keyword(s):

Detection Efficiency ◽

False Alarms ◽

Chi Square ◽

Secure Storage ◽

Chi Square Test ◽

Complex Detection ◽

Android Applications ◽

Malicious Apps ◽

Flow Detection ◽

Static Detection

Android devices are currently widely used in many fields, such as automatic control, embedded systems, the Internet of Things and so on. At the same time, Android applications (apps) always use multiple permissions, and permissions can be abused by malicious apps that disclose users’ privacy or breach the secure storage of information. FlowDroid has been extensively studied as a novel and highly precise static taint analysis for Android applications. Aiming at the problem of complex detection and false alarms in FlowDroid, an improved static detection method based on feature permission and risk rating is proposed. Firstly, the Chi-square test is used to extract correlated permissions related to malicious apps, and mutual information is used to cluster the permissions to generate feature permission clusters. Secondly, risk calculation method based on permissions and combinations of permissions are proposed to identify dangerous data flows. Experiments show that this method can significantly improve detection efficiency while maintaining the accuracy of dangerous data flow detection.

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Intravitreal Anti-Vascular Endothelial Growth Factor Agents for the Treatment of Diabetic Retinopathy: A Review of the Literature

Pharmaceutics ◽

10.3390/pharmaceutics13081137 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1137

Author(s):

Irini Chatziralli ◽

Anat Loewenstein

Keyword(s):

Diabetic Retinopathy ◽

Vitreous Hemorrhage ◽

Fundus Photography ◽

Panretinal Photocoagulation ◽

Wide Field ◽

Vascular Endothelial ◽

Keywords Diabetic Retinopathy ◽

Anti Vegf ◽

The Impact

Background: Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population. The purpose of this review is to gather the existing literature regarding the use of the approved anti-vascular endothelial growth (anti-VEGF) agents in the treatment of DR. Methods: A comprehensive literature review in PubMed engine search was performed for articles written in English language up to 1 July 2021, using the keywords “diabetic retinopathy”, “ranibizumab”, “aflibercept”, and “anti-VEGF”. Emphasis was given on pivotal trials and recent robust studies. Results: Intravitreal anti-VEGF agents have been found to significantly improve visual acuity and reduce retinal thickness in patients with diabetic macular edema (DME) in a long-term follow-up ranging from 1 to 5 years and are considered the standard-of-care in such patients. Regarding DR, intravitreal anti-VEGF agents provided ≥2-step improvement in DR severity on color fundus photography in about 30–35% of patients with NPDR at baseline, in the majority of clinical trials originally designed to evaluate the efficacy of intravitreal anti-VEGF agents in patients with DME. Protocol S and CLARITY study have firstly reported that intravitreal anti-VEGF agents are non-inferior to panretinal photocoagulation (PRP) in patients with proliferative DR (PDR). However, the use of new imaging modalities, such as optical coherence tomography-angiography and wide-field fluorescein angiography, reveals conflicting results about the impact of anti-VEGF agents on the regression of retinal non-perfusion in patients with DR. Furthermore, one should consider the high “loss to follow-up” rate and its devastating consequences especially in patients with PDR, when deciding to treat the latter with intravitreal anti-VEGF agents alone compared to PRP. In patients with PDR, combination of treatment of intravitreal anti-VEGF agents and PRP has been also supported. Moreover, in the specific case of vitreous hemorrhage or tractional retinal detachment as complications of PDR, intravitreal anti-VEGF agents have been found to be beneficial as an adjunct to pars plana vitrectomy (PPV), most commonly given 3–7 days before PPV, offering reduction in the recurrence of vitreous hemorrhage. Conclusions: There is no general consensus regarding the use of intravitreal anti-VEGF agents in patients with DR. Although anti-VEGF agents are the gold standard in the treatment of DME and seem to improve DR severity, challenges in their use exist and should be taken into account in the decision of treatment, based on an individualized approach.

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