- ID:
- ivo://CDS.VizieR/J/other/JHA/47.294
- Title:
- Ilkhanid star table (1232)
- Short Name:
- J/other/JHA/47.2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Ilkhani zij compiled by Nasir al-Din al-Tusi and his colleagues in the first period of the astronomical activities (the 1260s and early 1270s) in the Maragha observatory includes a star table collecting important observations of Islamic astronomers from the early ninth century through the third quarter of the thirteenth century, including the Mumtahan astronomers, Ibn al-A'lam, Ibn Yunus, as well as the Maragha astronomers themselves. This table gives the ecliptical coordinates of 18 bright stars in comparison with Ptolemy's corresponding values. This medieval bright star table is especially interesting for two reasons: first, it provides reliable evidence for the examination of the accuracy of the observations made and the instruments employed (notably, an armillary sphere) in the Maragha observatory. Second, it facilitates a comparative study of the accuracy of stellar observations in medieval Middle Eastern astronomy in the period in question. We have obtained the result that the Maragha astronomers observed more accurate star longitudes than did their predecessors, while for the latitudes, all Islamic observers appear to have gained about the same degree of accuracy. We also discuss two delicate matters raised by this table: first, the problem of the use of the two different values for the rate of precession by the Maragha astronomers in order to convert earlier star longitudes to the epoch of the Ilkhani zij (1{deg}/66 years for Ptolemy's longitudes and 1{deg}/70 years for those measured by their Islamic predecessors); second, the change in the star latitudes essentially related to the various values measured by Ptolemy and the Islamic astronomers represented side-by-side in it. Finally, we briefly discuss a small celestial globe designed by the son of Mu'ayyad al-Din al-'Urdi, the instrument-maker of the Maragha observatory.
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- ID:
- ivo://CDS.VizieR/J/A+AS/117/467
- Title:
- Image of Galaxies data-base II.
- Short Name:
- J/A+AS/117/467
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A preliminary list of 68.040 galaxies was built from extraction of 35.841 digitized images of the Palomar Sky Survey (Paper I, 1996A&A...311...12P). For each galaxy, the basic parameters are obtained: coordinates, diameter, axis ratio, total magnitude, position angle. On this preliminary list, we apply severe selection rules to get a catalog of 28.000 galaxies, well identified and well documented. For each parameter, a comparison is made with standard measurements. The accuracy of the raw photometric parameters is quite good despite of the simplicity of the method. Without any local correction, the standard error on the total magnitude is about 0.5 magnitude up to a total magnitude of B_T_=17. Significant secondary effects are detected concerning the magnitudes: distance to plate center effect and air-mass effect. The description of the construction of the catalog is given in Paturel et al. 1996 and Garnier et al. 1996. Galaxies are detected on POS-I and cross-identified with galaxies from the LEDA database (http://www-obs.univ-lyon1.fr/leda/)
- ID:
- ivo://CDS.VizieR/J/A+A/603/A68
- Title:
- Images of molecular and ionized gas around Sgr A*
- Short Name:
- J/A+A/603/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report serendipitous detections of line emission with the Atacama Large Millimeter/submillimeter Array (ALMA) in bands 3, 6, and 7 in the central parsec down to within 1" around Sgr A* at an up to now highest resolution (<0.5") view of the Galactic center (GC) in the submillimeter (sub-mm) domain. From the 100GHz continuum and the H39{alpha} emission we obtain a uniform electron temperature around Te~6000K for the minispiral. The spectral index (S{prop.to}{nu}^{alpha}^) of Sagittarius A* (Sgr A*) is ~0.5 at 100-250GHz and ~0.0 at 230-340GHz. The bright sources in the center show spectral indices around -0.1 implying Bremsstrahlung emission, while dust emission is emerging in the minispiral exterior. Apart from CS, which is most widespread in the center, H^13^CO^+^, HC_3_N, SiO, SO, C_2_H, CH_3_OH, ^13^CS and N_2_H+ are also detected. The bulk of the clumpy emission regions is at positive velocities and in a region confined by the minispiral northern arm (NA), bar, and the sources IRS 3 and 7. Although partly spatially overlapping with the radio recombination line (RRL) emission at same negative velocities, the relation to the minispiral remains unclear. A likely explanation is an infalling clump consisting of denser cloud cores embedded in diffuse gas. This central association (CA) of clouds shows three times higher CS/X (X: any other observed molecule) ratios than the circumnuclear disk (CND) suggesting a combination of higher excitation, by a temperature gradient and/or infrared (IR) pumping, and abundance enhancement due to UV and/or X-ray emission. Hence, we conclude that this CA is closer to the center than the CND. Moreover, we find molecular line emission at velocities up to 200km/s. Apart from the CA, we identified two intriguing regions in the CND. One region shows emission in all molecular species and higher energy levels tested in this and previous observations and contains a methanol class I maser. The other region shows similar behavior of the line ratios such as the CA. Outside the CND, we find the traditionally quiescent gas tracer N_2_H^+^ coinciding with the largest IR dark clouds (IRDC) in the field. Methanol emission is found at and around previously detected methanol class I masers in the same region. We propose to make these particular regions subject to further studies in the scope of hot core, cold core, and extreme photon and/or X-ray dominated region (PDR/XDR) chemistry and consequent star formation in the central few parsecs.
- ID:
- ivo://CDS.VizieR/J/A+A/544/L6
- Title:
- Images of two DQ white dwarfs
- Short Name:
- J/A+A/544/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intensity profiles of the C2 Swan bands in cool DQ white dwarfs cannot be adequately fitted with models that otherwise succesfully reproduce spectral features of the molecule CH in these stars. Initial modelling showed that a two-component atmosphere in the style of a spot might be able to solve the problem. We photometrically observed the two cool DQ white dwarfs GJ1117 and EGGR78 to search for variability caused by stellar spots. We have not found any such variability, but we estimate the effects of hypothetical spots on lightcurves. We also estimate detection probabilities for spots in different configurations. Alternative explanations of the problem are needed and briefly discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/643/680
- Title:
- Imaging and spectroscopy around PKS 0405-123
- Short Name:
- J/ApJ/643/680
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a galaxy survey of the field surrounding PKS 0405-123 performed with the WFCCD spectrometer at Las Campanas Observatory. The survey is comprised of two data sets: (1) a greater than 95% complete survey to R=20mag of the field centered on PKS 0405-123 with 10' radius (L~0.1L* and radius of 1Mpc at z=0.1); and (2) a set of four discontiguous (i.e., non-overlapping), flanking fields covering ~1deg^2^ area with completeness ~90% to R=19.5mag. With these data sets, one can examine the local and large-scale galactic environment of the absorption systems identified toward PKS 0405-123. In this paper, we focus on the O VI systems analyzed in Paper I (Prochaska et al., 2004, Cat. <J/ApJ/617/718>). The results suggest that this gas arises in a diverse set of galactic environments including the halos of individual galaxies, galaxy groups, filamentary-like structures, and also regions devoid of luminous galaxies. In this small sample, there are no obvious trends between galactic environment and the physical properties of the gas. Furthermore, we find similar results for a set of absorption systems with comparable NHI but no detectable metal lines. The observations indicate that metals are distributed throughout a wide range of environments in the local universe. Future papers in this series will address the distribution of galactic environments associated with metal-line systems and the Ly forest based on data for over 10 additional fields. All of the spectra and fits tables are available at http://www.ucolick.org/~xavier/WFCCDOVI/
- ID:
- ivo://CDS.VizieR/J/AJ/148/117
- Title:
- Imaging and spectroscopy in Lynx W
- Short Name:
- J/AJ/148/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RX J0848.6+4453 (Lynx W) at redshift 1.27 is part of the Lynx Supercluster of galaxies. We present an analysis of the stellar populations and star formation history for a sample of 24 members of the cluster. Our study is based on deep optical spectroscopy obtained with Gemini North combined with imaging data from Hubble Space Telescope. Focusing on the 13 bulge-dominated galaxies for which we can determine central velocity dispersions, we find that these show a smaller evolution with redshift of sizes and velocity dispersions than reported for field galaxies and galaxies in poorer clusters. Our data show that the galaxies in RX J0848.6+4453 populate the fundamental plane (FP) similar to that found for lower-redshift clusters. The zero-point offset for the FP is smaller than expected if the cluster's galaxies are to evolve passively through the location of the FP we established in our previous work for z=0.8-0.9 cluster galaxies and then to the present-day FP. The FP zero point for RXJ0848.6+4453 corresponds to an epoch of last star formation at z_form_=1.95_-0.15_^+0.22^. Further, we find that the spectra of the galaxies in RXJ0848.6+4453 are dominated by young stellar populations at all galaxy masses and in many cases show emission indicating low-level ongoing star formation. The average age of the young stellar populations as estimated from the strength of the high-order Balmer line H{zeta} is consistent with a major star formation episode 1-2Gyr prior, which in turn agrees with z_form_=1.95. These galaxies dominated by young stellar populations are distributed throughout the cluster. We speculate that low-level star formation has not yet been fully quenched in the center of this cluster, possibly because the cluster is significantly poorer than other clusters previously studied at similar redshifts, which appear to have very little ongoing star formation in their centers. The mixture in RXJ0848.6+4453 of passive galaxies with young stellar populations and massive galaxies still experiencing some star formation appears similar to the galaxy populations recently identified in two z{approx}2 clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/145/77
- Title:
- Imaging and spectroscopy in three galaxy clusters
- Short Name:
- J/AJ/145/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of stellar populations and evolutionary history of galaxies in three similarly rich galaxy clusters MS0451.6-0305 (z=0.54), RXJ0152.7-1357 (z=0.83), and RXJ1226.9+3332 (z=0.89). Our analysis is based on high signal-to-noise ground-based optical spectroscopy and Hubble Space Telescope imaging for a total of 17-34 members in each cluster. Using the dynamical masses together with the effective radii and the velocity dispersions, we find no indication of evolution of sizes or velocity dispersions with redshift at a given galaxy mass. We establish the Fundamental Plane (FP) and scaling relations between absorption line indices and velocity dispersions. We confirm that the FP is steeper at z~0.86 compared to the low-redshift FP, indicating that under the assumption of passive evolution the formation redshift, z_form_, depends on the galaxy velocity dispersion (or alternatively mass). At a velocity dispersion of {sigma}=125km/s (Mass=10^10.55^M_{sun}_) we find z_form_=1.24+/-0.05, while at {sigma}=225km/s (Mass=10^11.36^M_{sun}_) the formation redshift is z_form_=1.95^+0.3^_-0.2_, for a Salpeter initial mass function. The three clusters follow similar scaling relations between absorption line indices and velocity dispersions as those found for low-redshift galaxies. The zero point offsets for the Balmer lines depend on cluster redshifts. However, the offsets indicate a slower evolution, and therefore higher formation redshift, than the zero point differences found from the FP, if interpreting the data using a passive evolution model. Specifically, the strength of the higher order Balmer lines H{delta} and H{gamma} implies z_form_>2.8. The scaling relations for the metal indices in general show small and in some cases insignificant zero point offsets, favoring high formation redshifts for a passive evolution model.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A70
- Title:
- Imaging GRB 980425 in millimetic and submm
- Short Name:
- J/A+A/562/A70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gamma-ray bursts (GRBs) have been proposed as a tool to study star formation in the Universe, so it is crucial to investigate whether their host galaxies and immediate environments are in any way special compared with other star-forming galaxies. Here we present spatially resolved maps of dust emission of the host galaxy of the closest known GRB 980425 at z=0.0085 using our new high-resolution observations from Herschel, APEX, ALMA and ATCA. We modeled the spectral energy distributions of the host and of the star-forming region displaying the Wolf-Rayet signatures in the spectrum (WR region), located 800pc away from the GRB position. The host is characterised by low dust content and high fraction of UV-visible star-formation, similar to other dwarf galaxies. Such galaxies are abundant in the local universe, so it is not surprising to find a GRB in one of them, assuming the correspondence between the GRB rate and star-formation. The WR region contributes substantially to the host emission at the far-infrared, millimeter and radio wavelengths and we propose this to be a consequence of its high gas density. If dense environments are also found close to the positions of other GRBs, then the ISM density should also be considered as an important factor influencing whether a given stellar population can produce a GRB, in a similar way as metallicity.
- ID:
- ivo://CDS.VizieR/J/PASJ/57/881
- Title:
- Imaging of high-redshift Lyman alpha emitters
- Short Name:
- J/PASJ/57/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of our intermediate-band optical imaging survey for high-z Ly{alpha} emitters (LAEs) using the prime focus camera, Suprime-Cam, on the 8.2m Subaru telescope. In our survey, we used eleven filters: four broad-band filters (B, R_C_, i', and z') and seven intermediate-band filters covering from 500nm to 720nm. We call this imaging program the Mahoroba-11. The seven intermediate-band filters were selected from a series of IA filters, which is the Suprime-Cam intermediate-band filter system, whose spectral resolution is R=23. Our survey was made in a 34'x27' sky area in the Subaru XMM-Newton Deep Survey Field. We found 409 IA-excess objects, which provided us with a large photometric sample of strong emission-line objects. Applying the photometric redshift method to this sample, we obtained a new sample of 198 LAE candidates at 3<z<5. We found no evidence for evolutions of the number density and the star-formation rate density (SFRD) for LAEs with logL(Ly{alpha})(erg/s)>42.67 between z~3 and z~5.
- ID:
- ivo://CDS.VizieR/J/AJ/154/245
- Title:
- Imaging survey of Spitzer-detected debris disks
- Short Name:
- J/AJ/154/245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a joint high-contrast imaging survey for planets at the Keck and Very Large Telescope of the last large sample of debris disks identified by the Spitzer Space Telescope. No new substellar companions were discovered in our survey of 30 Spitzer-selected targets. We combine our observations with data from four published surveys to place constraints on the frequency of planets around 130 debris disk single stars, the largest sample to date. For a control sample, we assembled contrast curves from several published surveys targeting 277 stars that do not show infrared excesses. We assumed a double power-law distribution in mass and semimajor axis (SMA) of the form f(m,a)=Cm^{alpha}^{alpha}^{beta}^, where we adopted power-law values and logarithmically flat values for the mass and SMA of planets. We find that the frequency of giant planets with masses 5-20 M_Jup_ and separations 10-1000 au around stars with debris disks is 6.27% (68% confidence interval 3.68%-9.76%), compared to 0.73% (68% confidence interval 0.20%-1.80%) for the control sample of stars without disks. These distributions differ at the 88% confidence level, tentatively suggesting distinctness of these samples.