- ID:
- ivo://CDS.VizieR/J/A+A/501/563
- Title:
- HKs photometry in the Arches cluster
- Short Name:
- J/A+A/501/563
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The massive Arches cluster near the Galactic center should be an ideal laboratory for investigating massive star formation under extreme conditions. But it comes at a high price: the cluster is hidden behind several tens of magnitudes of visual extinction. Severe crowding requires space or AO-assisted instruments to resolve the stellar populations, and even with the best instruments interpreting the data is far from direct. Several investigations using NICMOS and the most advanced AO imagers on the ground revealed an overall top-heavy IMF for the cluster, with a very flat IMF near the center. There are several effects, however, that could potentially bias these results, in particular the strong differential extinction and the problem of transforming the observations into a standard photometric system in the presence of strong reddening. We present new observations obtained with the NAOS-Conica (NACO) AO-imager on the VLT. The problem of photometric transformation is avoided by working in the natural photometric system of NACO, and we use a Bayesian approach to determine masses and reddenings from the broad-band IR colors. A global value of Gamma=-1.1+/-0.2 for the high-mass end (M>10M_{sun}_) of the IMF is obtained, and we conclude that a power law of Salpeter slope cannot be discarded for the Arches cluster. The flattening of the IMF towards the center is confirmed, but is less severe than previously thought. We find Gamma=-0.88+/-0.20, which is incompatible with previous determinations. Within 0.4pc we derive a total mass of ~2.0(+/-0.6)x10^4^M_{sun}_ for the cluster and a central mass density rho=2(+/-0.4)x10^5^M_{sun}_/pc^3^ that confirms Arches as the densest known young massive cluster in the Milky Way.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/244/16
- Title:
- HLF photometric catalog in GOODS-S v2.0
- Short Name:
- J/ApJS/244/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This manuscript describes the public release of the Hubble Legacy Fields (HLF) project photometric catalog for the extended GOODS-South region from the Hubble Space Telescope (HST) archival program AR-13252. The analysis is based on the version 2.0 HLF data release that now includes all ultraviolet (UV) imaging, combining three major UV surveys. The HLF data combines over a decade worth of 7475 exposures taken in 2635 orbits totaling 6.3Ms with the HST Advanced Camera for Surveys Wide Field Channel (ACS/WFC) and the Wide Field Camera 3 (WFC3) UVIS/IR Channels in the greater GOODS-S extragalactic field, covering all major observational efforts (e.g., GOODS, GEMS, CANDELS, ERS, UVUDF, and many other programs; see Illingworth+ arXiv:1606.00841). The HLF GOODS-S catalogs include photometry in 13 bandpasses from the UV (WFC3/UVIS F225W, F275W, and F336W filters), optical (ACS/WFC F435W, F606W, F775W, F814W and F850LP filters), to near-infrared (WFC3/IR F098M, F105W, F125W, F140W and F160W filters). Such a data set makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range from high-resolution mosaics that are largely contiguous. Here, we describe a photometric analysis of 186474 objects in the HST imaging at wavelengths 0.2-1.6{mu}m. We detect objects from an ultra-deep image combining the PSF-homogenized and noise-equalized F850LP, F125W, F140W, and F160W images, including Gaia astrometric corrections. SEDs were determined by carefully taking the effects of the point-spread function in each observation into account.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1289
- Title:
- H magnitude and radial velocities of A1644
- Short Name:
- J/AJ/122/1289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss H-band (1.65{mu}m) near-infrared photometry of the central 9h^-2^Mpc^2^ of Abell 1644 (A1644) to a limiting M_H_~M*_H_+3 (throughout this paper H_0_=100h*km/s/Mpc). here are 861 galaxies in the photometric survey region. We also measured radial velocities of 155 galaxies; 141 of these are cluster members within 2.44h^-1^Mpc of the cluster center.
- ID:
- ivo://CDS.VizieR/J/ApJS/96/123
- Title:
- H-magnitudes of spiral galaxies
- Short Name:
- J/ApJS/96/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The H-magnitude aperture data published by the Aaronson et al. collaboration (See references) over a 10 year period is collected into a homogeneous data set of 1731 observations of 665 galaxies. Ninety-six percent of these galaxies have isophotal diameters and axial ratios determined by the Third Reference Catalogue of Bright Galaxies (RC3; de Vaucouleurs et al., 1991, Cat. <VII/155>), the most self-consistent set of optical data currently available. The precepts governing the optical data in the RC3 are systematically different from those of the Second Reference Catalogue (de Vaucouleurs, de Vaucouleurs, & Corwin 1976, Cat .<VII/112>), which were used by Aaronson et al. for their original analyses of galaxy peculiar motions. This in turn leads to systematic differences in growth curves and fiducial H-magnitudes, prompting the present recalibration of the near-infrared Tully-Fisher relationship. New optically normalized H-magnitude growth curves are defined for galaxies of types S0 to Im, from which new values of fiducial H-magnitude, H^g^_-0.5_, are measured for the 665 galaxies. A series of internal tests show that these four standard growth curves are defined to an accuracy of 0.05mag over the interval 1.5<=log(A/D_g_)<=-0.2. Comparisons with the Aaronson et al. values of diameters, axial ratios, and fiducial H-magnitudes show the expected differences, given the different definitions of these parameters. The values of H^g^_-0.5_ are assigned quality indices: a quality value of 1 indicates an accuracy of less than 0.2mag, quality 2 indicates an accuracy of 0.2-0.35mag, and quality 3 indicates an accuracy of more than 0.35mag. Revised values of corrected H I velocity widths are also given, based on the new set of axial ratios defined by the RC3.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/2009
- Title:
- H narrow-band imaging of XMMU J2235.3-2557
- Short Name:
- J/MNRAS/411/2009
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a narrow-band photometric study of the massive galaxy cluster XMMU J2235.3-2557 at z=1.39. We obtained deep H narrow-band imaging with the Near InfraRed Imager and Spectrometer on Gemini North, corresponding to H{alpha} emission at the cluster's redshift. Our sample consists of 82 galaxies within a radius of ~500kpc, 10 of which are spectroscopically confirmed cluster members. 16 galaxies are identified as excess line-emitters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/3652
- Title:
- H narrow-band imaging of XMMU J2235.3-2557
- Short Name:
- J/MNRAS/423/3652
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an extended narrow-band H{alpha} study of the massive galaxy cluster XMMU J2235.3-2557 at z=1.39. This paper represents a follow-up study to our previous investigation of star formation in the cluster centre, extending our analysis out to a projected cluster radius of 1.5Mpc. Using the Near InfraRed Imager and Spectrograph on Gemini North Telescope we obtained deep H narrow-band imaging corresponding to the rest-frame wavelength of H{alpha} at the cluster's redshift. We identify a total of 163 potential cluster members in both pointings, excluding stars based on their near-infrared colours derived from VLT/HAWK-I imaging. Of these 163 objects 14 are spectroscopically confirmed cluster members, and 20 per cent are excess line emitters. We find no evidence of star formation activity within a radius of 200 kpc of the brightest cluster galaxy in the cluster core. Dust-corrected star formation rates (SFRs) of excess emitters outside this cluster quenching radius, R_Q_~200kpc, are on average <SFR>=2.7+/-1.0M_{sun}_/yr, but do not show evidence of increasing SFRs towards the extreme 1.5Mpc radius of the cluster. No individual cluster galaxy exceeds an SFR of 6M_{sun}_/yr. Massive galaxies (logM*/M_{sun}_>10.75) all have low specific SFRs (SSFRs, i.e. SFR per unit stellar mass). At fixed stellar mass, galaxies in the cluster centre have lower SSFRs than the rest of the cluster galaxies, which in turn have lower SSFRs than field galaxies at the same redshift by a factor of a few to 10. For the first time we can demonstrate through measurements of individual SFRs that already at very early epochs (at an age of the Universe of ~4.5Gyr) the suppression of star formation is an effect of the cluster environment which persists at fixed galaxy stellar mass.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A77
- Title:
- HOBYS: 46 MDCs found in NGC 6334
- Short Name:
- J/A+A/602/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To constrain models of high-mass star formation, the Herschel-HOBYS key program aims at discovering massive dense cores (MDCs) able to host the high-mass analogs of low-mass prestellar cores, which have been searched for over the past decade. We here focus on NGC 6334, one of the best-studied HOBYS molecular cloud complexes. We used Herschel/PACS and SPIRE 70-500{mu}m images of the NGC 6334 complex complemented with (sub)millimeter and mid-infrared data. We built a complete procedure to extract ~0.1pc dense cores with the getsources software, which simultaneously measures their far-infrared to millimeter fluxes. We carefully estimated the temperatures and masses of these dense cores from their spectral energy distributions (SEDs). We also identified the densest pc-scale cloud structures of NGC 6334, one 2pcx1pc ridge and two 0.8pcx0.8pc hubs, with volume-averaged densities of ~10^5^cm^-3^. A cross-correlation with high-mass star formation signposts suggests a mass threshold of 75M_{sun}_ for MDCs in NGC 6334. MDCs have temperatures of 9.5-40K, masses of 75-1000M_{sun}_, and densities of 1x10^5^-7x10^7^cm^-3^. Their mid-infrared emission is used to separate 6 IR-bright and 10 IR-quiet protostellar MDCs while their 70{mu}m emission strength, with respect to fitted SEDs, helps identify 16 starless MDC candidates. The ability of the latter to host high-mass prestellar cores is investigated here and remains questionable. An increase in mass and density from the starless to the IR-quiet and IR-bright phases suggests that the protostars and MDCs simultaneously grow in mass. The statistical lifetimes of the high-mass prestellar and protostellar core phases, estimated to be 1-7x10^4^yr and at most 3x10^5^yr respectively, suggest a dynamical scenario of high-mass star formation. The present study provides good mass estimates for a statistically significant sample, covering the earliest phases of high-mass star formation. High-mass prestellar cores may not exist in NGC 6334, favoring a scenario presented here, which simultaneously forms clouds, ridges, MDCs, and high-mass protostars.
2628. Hogg 16 peculiar stars
- ID:
- ivo://CDS.VizieR/J/other/NewA/58.1
- Title:
- Hogg 16 peculiar stars
- Short Name:
- J/other/NewA/58.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of chemically peculiar (CP) stars in open clusters provides valuable information about their evolutionary status. Their detection can be performed using the Delta-a photometric system, which maps a characteristic flux depression at lambda 5200{AA}. This paper aims at studying the occurrence of CP stars in the earliest stages of evolution of a stellar population by applying this technique to Hogg 16, a very young Galactic open cluster (about 25Myr). We identified several peculiar candidates: two B-type stars with a negative Delta-a index (CD-60 4701, CPD-60 4706) are likely emission-line (Be) stars, even though spectral measurements are necessary for a proper classification of the second one; a third object (CD-60 4703), identified as a Be candidate in literature, appears to be a background B-type supergiant with no significant Delta-a index, which does not rule out the possibility that it is indeed peculiar as the normality line of Delta-a for supergiants has not been studied in detail yet. A fourth object (CD-60 4699) appears to be a magnetic CP star of 8 Msun, but obtained spectral data seem to rule out this hypothesis. Three more magnetic CP star candidates are found in the domain of early F-type stars. One is a probable nonmember and close to the border of significance, but the other two are probably pre-main sequence cluster objects. This is very promising, as it can lead to very strong constraints to the diffusion theory. Finally, we derived the fundamental parameters of Hogg 16 and provide for the first time an estimate of its metal content.
- ID:
- ivo://CDS.VizieR/II/75
- Title:
- Homegeneous RI magnitudes in Kron system
- Short Name:
- II/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue (file "mean") contains homogeneous data in the photoelectric photometric system of Kron and Smith. The R magnitude and the R-I colour index have been collected from the literature published before January 1982. The homogenization method used in file "mean" has been described by Nicolet B. (1978, Astron. Astrophys. Suppl. 34,1).
- ID:
- ivo://CDS.VizieR/II/168
- Title:
- Homogeneous Means in the UBV System
- Short Name:
- II/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present catalog supersedes an earlier edition of Nicolet (1978). It is a collection of weighted mean photoelectric values (V, B-V, U-B) for stars measured in the UBV system. The mean values were computed by combining all individual measurements compiled in the catalog of Mermilliod (1987), except those that were clearly found to be erroneous for some reason or another. Some newer observations compiled since 1987 are also included in the means. The procedure for computing the homogeneous means involved the calculation of normal averages weighted by the number of observations in each list (unity when not published). New weights are assigned based on the deviation of each value from the previous mean, then a new weighted mean is computed. This technique is not as rigorous as that used by Nicolet (comparison of each list with the standard system master list), but the latter cannot often be realized effectively in practice, since many lists do not contain enough stars in common with a standard list. Also, there are now so many references (more than 1500) that it is not feasible to analyze each publication with respect to a standard list. This edition of the catalog contains 92964 stars measured since the introduction of the UBV system in 1953. The data included are star identification in the Geneva coded numbering system, double and variable codes, UBV data and their standard deviations, and number of observations. A second file contains the definition of the coded numbering system. The catalog was prepared at the Institut d'Astronomie de l'Universite de Lausanne in Geneva.
