- ID:
- ivo://CDS.VizieR/J/A+A/584/A73
- Title:
- Sunspot areas and tilt angles
- Short Name:
- J/A+A/584/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extending the knowledge about the properties of solar cycles into the past is essential for understanding the solar dynamo. This paper aims to estimate areas of sunspots observed by Schwabe in 1825-1867 and to calculate the tilt angles of sunspot groups. The sunspot sizes in Schwabe's drawings are not to scale and need to be converted into physical sunspot areas. We employed a statistical approach assuming that the area distribution of sunspots was the same in the 19th century as it was in the 20th century.
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18302. Sunspot on 1921-2011
- ID:
- ivo://CDS.VizieR/J/A+A/601/A106
- Title:
- Sunspot on 1921-2011
- Short Name:
- J/A+A/601/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Long-term sunspot observations are key to understanding and predicting the solar activities and its effects on space weather. Consistent observations, which are crucial for long-term variations studies, are generally not available due to upgradation/modification of observatories over the course of time. We present data for a period of 90 yr acquired from persistent observation at the Kodaikanal observatory in India. We aim to build a uniform sunspot area time series along with their positions for a 90-yr period between 1921 and 2011, as obtained from the newly digitized and calibrated white-light images from the Kodaikanal observatory. Our aim is to compare this new time series with known sources and confirm some of the earlier reported results with additional new aspects. We use an advanced semi-automated algorithm to detect the sunspots form each calibrated white-light image. Area, longitude and latitude of each of the detected sunspots are derived. Implementation of a semi-automated method is extremely necessary in such studies as it minimizes the human bias in the detection procedure. Daily, monthly, and yearly sunspot area variations, obtained from the Kodaikanal, compared well with the Greenwich sunspot area data. We find an exponentially decaying distribution for the individual sunspot area for each of the solar cycles. Analyzing the histograms of the latitudinal distribution of the detected sunspots, we find Gaussian distributions, in both the hemispheres, with centers at ~15{deg} latitude. The height of the Gaussian distributions are different for the two hemispheres for a particular cycle. Using our data, we show clear presence of Waldmeier effect, which correlates the rise time with the cycle amplitude. Using the wavelet analysis, we explored different periodicities on different time scales present in the sunspot area times series.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A46
- Title:
- Sunspot penumbra and umbral flashes models
- Short Name:
- J/A+A/627/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The solar chromosphere and the lower transition region are believed to play a crucial role in the heating of the solar corona. Models that describe the chromosphere (and the lower transition region), accounting for its highly dynamic and structured character are, so far, found to be lacking. This is partly due to the breakdown of complete frequency redistribution (CRD) in the chromospheric layers and also because of the difficulty in obtaining complete sets of observations that adequately constrain the solar atmosphere at all relevant heights. We aim to obtain semi-empirical model atmospheres that reproduce the features of the MgII H & K line profiles that sample the middle chromosphere with focus on a sunspot. We used spectropolarimetric observations of the CaII 8542{AA} spectra obtained with the Swedish 1-m Solar Telescope and used NICOLE inversions to obtain semi-empirical model atmospheres for different features in and around a sunspot. These were used to synthesize MgII H & K spectra using the RH1.5D code, which we compared with observations taken with the Interface Region Imaging Spectrograph (IRIS). Comparison of the synthetic profiles with IRIS observations reveals that there are several areas, especially in the penumbra of the sunspot, where most of the observed MgII H & K profiles are very well reproduced. In addition, we find that supersonic hot downflows, present in our collection of models in the umbra, lead to synthetic profiles that agree well with the IRIS MgII H & K profiles, with the exception of the line core. We put forward and make available four semi-empirical model atmospheres. Two for the penumbra, reflecting the range of temperatures obtained for the chromosphere, one for umbral flashes, and a model representative of the quiet surroundings of a sunspot. These are available in electronic as well as in table formats.
- ID:
- ivo://CDS.VizieR/VI/138
- Title:
- Sunspots catalogues, 1853-1870
- Short Name:
- VI/138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the 19th century, several astronomers observed sunspots obtaining their positions and, occasionaly, their areas. These observations were published in large tables that have remained in the anonymity until now. The observations made by Richard C. Carrington, Christian H. F. Peters and Warren de la Rue (and their respective collaborators) were published in different articles. The total number of positions evaluated by these three observers was of 26,641 (Carrington: 4,900; Peters: 14,040; and de la Rue: 7,701). In this work, we transformed more of 400 pages of numerical tables to a machine readable format. Moreover, we carried out a cursory analysis to detect possible mistakes in the reading or in the original transcription.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A21
- Title:
- Sun UV spectrum (06/06/2008-26/04/2009)
- Short Name:
- J/A+A/600/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SOLar SPECtrum (SOLSPEC) experiment is part of the Solar Monitoring Observatory (SOLAR) payload, and has been externally mounted on the Columbus module of the International Space Station (ISS) since 2008. SOLAR/SOLSPEC combines three absolutely calibrated double monochromators with concave gratings for measuring the solar spectral irradiance (SSI) from 166nm to 3088nm. This physical quantity is a key input for studies of climatology, planetary atmospheres, and solar physics. A general description of the instrument is given, including in-flight operations and performance of the ultraviolet (UV) channel from 175nm to 340nm. We developed a range of processing and correction methods, which are described in detail. For example, methods for correcting thermal behavior effects, instrument linearity, and especially the accuracy of the wavelength and absolute radiometric scales have been validated by modeling the standard uncertainties. The deliverable is a quiet Sun UV reference solar spectrum as measured by SOLAR/SOLSPEC during the minimum of solar activity prior to cycle 24. Comparisons with other instruments measuring SSI are also presented.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A108
- Title:
- Sun velocities from GOLF instrument
- Short Name:
- J/A+A/617/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The recent claims of g-mode detection have restarted the search for these potentially extremely important modes. These claims can be reassessed in view of the different data sets available from the SoHO instruments and ground-based instruments. We produce a new calibration of the GOLF data with a more consistent p-mode amplitude and a more consistent time shift correction compared to the time series used in the past. The calibration of 22 years of GOLF data is done with a simpler approach that uses only the predictive radial velocity of the SoHO spacecraft as a reference. Using p modes, we measure and correct the time shift between ground- and space-based instruments and the GOLF instrument. The p-mode velocity calibration is now consistent to within a few percent with other instruments. The remaining time shifts are within +/-5s for 99.8% of the time series.
- ID:
- ivo://CDS.VizieR/J/MNRAS/376/1073
- Title:
- Sunyaev-Zel'dovich effect in galaxy clusters
- Short Name:
- J/MNRAS/376/1073
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a search for evidence of the short wavelength increment in the Sunyaev-Zel'dovich (SZ) effect, we have analysed archival galaxy cluster data from the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope, resulting in the most complete pointed survey of clusters at 850{mu}m to date. SCUBA's 850{mu}m passband overlaps the peak of the SZ increment. The sample consists of 44 galaxy clusters in the range 0<z<1.3. Maps of each of the clusters have been made and sources have been extracted; as an ancillary product, we generate the most thorough galaxy cluster point source list yet from SCUBA. 17 of these clusters are free of obvious active galactic nuclei (AGN) and have data deep enough to provide interesting measurements of the expected SZ signal.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/3
- Title:
- Sunyaev-Zel'dovich galaxy clusters surveyed by ACT
- Short Name:
- J/ApJS/253/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 4195 optically confirmed Sunyaev-Zel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13211deg^2^ of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04<z<1.91 (median z=0.52). The catalog contains 222 z>1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M_500c_>3.8x10^14^M_{sun}_, evaluated at z=0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2.4'. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566deg^2^), the Hyper Suprime-Cam Subaru Strategic Program (469deg^2^), and the Kilo Degree Survey (825deg^2^). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/4
- Title:
- SuperBoRG: search HST parallel imaging data
- Short Name:
- J/ApJS/253/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hubble Space Telescope (HST) has been providing tremendous survey efficiency via its pure-parallel mode by observing another field in parallel with the primary instrument in operation for the primary observation. In this study, we present a new archival project, SuperBoRG, which aims at compiling data taken in extragalactic parallel programs of HST with the Wide Field Camera 3 in the past decade, including pure-parallel (BoRG, HIPPIES, and COS-GTO) and coordinated-parallel (CLASH and RELICS) programs. The total effective area reaches ~0.41deg^2^ from 4.1Ms, or 47days, of observing time, which is the largest collection of optical-to-near-infrared imaging data of HST for extragalactic science. We reduce all data in a consistent manner with an updated version of our data reduction pipeline, including a new sky background subtraction step. When available, imaging data from the Spitzer Space Telescope are also included in photometric analyses. The data set consists of 316 independent sight lines and is highly effective for identification of high-z luminous sources (M_UV_<~-20mag) at z~7-12, helping to minimize the effects of cosmic variance. As a demonstration, we present three new z>~7 source candidates, including one luminous galaxy candidate at z_phot_~10.4 with M_UV_~-21.9mag; the best-fit spectral energy distribution implies a large amount of stellar mass (logM_*_/M_{sun}_~10) and moderate dust attenuation (A_V_~1.4mag), though the possibility of it being a low-z interloper cannot be completely rejected (~23%) with the current data set. The data set presented in this study is also suited for intermediate- and low-z science cases.
18310. SuperCLASS. I.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/1706
- Title:
- SuperCLASS. I.
- Short Name:
- J/MNRAS/495/1706
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy programme using the e-MERLIN interferometric array. The aim is to observe the sky at L-band (1.4GHz) to a r.m.s. of 7uJy/beam over an area of 1 square degrees centred on the Abell 981 supercluster. The main scientific objectives of the project are: (i) to detect the effects of weak lensing in the radio in preparation for similar measurements that will be made by the Square Kilometre Array (SKA); (ii) an extinction free census of star formation and AGN activity at z up to 1. In this paper we give an overview of the project including the science goals and multi-wavelength coverage before presenting the first data release. We have analysed around 400 hours of e-MERLIN data which has allowed us to create a DR1 mosaic covering an area ~0.26 square degrees to the full depth. These observations have been supplemented with complementary radio observations from the Karl G. Jansky Very Large Array (VLA) and optical/near infra-red observations taken with the Subaru, Canada-France-Hawaii and Spitzer Telescopes. The main data product is a catalogue of 887 sources detected by the VLA, of which 395 are detected by e-MERLIN and 197 of these are resolved. We have investigated the size, flux and spectral index properties of these sources and find them to be compatible with previous studies. Preliminary photometric redshifts, and an assessment of galaxy shapes measured in the radio data, combined with a radio-optical cross-correlation technique to probe cosmic shear in a supercluster environment, are presented in companion papers.