- ID:
- ivo://CDS.VizieR/J/A+A/456/905
- Title:
- JKs, i'g'r' photometry of C stars in NGC 6822
- Short Name:
- J/A+A/456/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a 2{deg}x2{deg} survey of NGC 6822 we have previously established that this Local Group dwarf irregular galaxy possesses a huge spheroid having more than one degree in length. This spheroid is in rotation but its rotation curve is known only within ~15' from the center. It is therefore critical to identify bright stars belonging to the spheroid to characterize, as far as possible, its outer kinematics. We use the new wide field near infrared imager CPAPIR, operated by the SMARTS consortium, to acquire J, K_s_ images of two 34.8'x34.8' areas in the outer spheroid to search for C stars. The colour diagram of the fields allows the identification of 192 C stars candidates but a study of the FWHM of the images permits the rejection of numerous non-stellar objects with colours similar to C stars. We are left with 75 new C stars, their mean K_s_ magnitude and mean colour are similar to the bulk of known NGC 6822 C stars. This outer spheroid survey confirms that the intermediate-age AGB stars are a major contributor to the stellar populations of the spheroid. The discovery of some 50 C stars well beyond the limit of the previously known rotation curve calls for a promising spectroscopic follow-up to a major axis distance of 40'.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/474/35
- Title:
- JKs photometry of C stars in IC10 and WLM
- Short Name:
- J/A+A/474/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The selection of AGB C and M stars from NIR colours has been done in recent years using adjustable criteria that are in needs of standardization if one wants to compare, in a coherent manner, properties of various populations. We intend to assess the NIR colour technique to identify C and M stars. We compare the NIR colours of several C stars previously identified from spectroscopy or narrow band techniques in WLM, IC 10 and NGC 6822. We demonstrate that very few M stars have (J-K)_0_>1.4 but a non negligible number of C stars are bluer than this limit. Thus, counts of M and C stars based on such limit do not produce pure samples. C/M ratios determined from NIR colours must be regarded as underestimates mainly because the M numbers include many warm C stars and also K stars if no blue limit is considered.
- ID:
- ivo://CDS.VizieR/J/ApJS/149/327
- Title:
- JKs photometry of local universe galaxies
- Short Name:
- J/ApJS/149/327
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents empirical results from a deep imaging survey of galaxies in the local universe at the J and Ks wavelengths. Three hundred ninety-one images have been obtained and calibrated using the same camera and filter set with the Steward Observatory 1.6m Kuiper Telescope on Mount Bigelow and the 2.3m Bok Telescope on Kitt Peak. The limiting magnitude is typically 22mag/arcsec at J and 21mag/arcsec at Ks. The central surface brightness, apparent magnitudes, sizes, scale lengths, and inclinations are tabulated from measurements made using these data. The purpose of this paper is to provide basic near-infrared data on a variety of galaxy types.
- ID:
- ivo://CDS.VizieR/J/A+A/466/501
- Title:
- JKs photometry of WLM galaxy carbon stars
- Short Name:
- J/A+A/466/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify the rich carbon star population of the Magellanic-type dwarf irregular galaxy WLM (Wolf-Lundmark-Melotte) and study its photometric properties from deep near-IR observations. The galaxy also exhibits a clear presence of oxygen-rich population. We derive a carbon to M-star ratio of C/M=0.56+/-0.12, relatively high in comparison with many galaxies. The spatial distribution of the AGB stars in WLM hints at the presence of two stellar complexes with a size of a few hundred parsecs. Using the HI map of WLM and the derived gas-to-dust ratio for this galaxy N(HI)/E(B-V)=60+/-10[10^21^at/cm^2^/mag] we re-determined the distance modulus of WLM from the IR photometry of four known Cepheids, obtaining (m-M)0=24.84+/-0.14mag. In addition, we determine the scale length of 0.75+/-0.14kpc of WLM disk in the J-band.
- ID:
- ivo://CDS.VizieR/J/A+A/612/L6
- Title:
- j-M law from dwarf to massive spirals
- Short Name:
- J/A+A/612/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a {LAMBDA} CDM Universe, the specific stellar angular momentum (j*) and stellar mass (M*) of a galaxy are correlated as a consequence of the scaling existing for dark matter haloes (jh{prop.to}2/3). The shape of this law is crucial to test galaxy formation models, which are currently discrepant especially at the lowest masses, allowing to constrain fundamental parameters, such as, for example, the retained fraction of angular momentum. In this study, we accurately determine the empirical j*-M* relation (Fall relation) for 92 nearby spiral galaxies (from S0 to Irr) selected from the Spitzer Photometry and Accurate Rotation Curves (SPARC) sample in the unprecedented mass range 7<~logM*/M_{sun}_<~11.5. We significantly improve all previous estimates of the Fall relation by determining j* profiles homogeneously for all galaxies, using extended HI rotation curves, and selecting only galaxies for which a robust j* could be measured (converged j*(<R) radial profile). We find the relation to be well described by a single, unbroken power-law j*{alpha}M*^{alpha}^ over the entire mass range, with {alpha}=0.55+/-0.02 and orthogonal intrinsic scatter of 0.17+/-0.01dex. We finally discuss some implications of this fundamental scaling law for galaxy formation models and, in particular, the fact that it excludes models in which discs of all masses retain the same fraction of the halo angular momentum.
- ID:
- ivo://CDS.VizieR/J/ApJ/868/133
- Title:
- j-M relation for disk and bulge type galaxies
- Short Name:
- J/ApJ/868/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We show that the stellar specific angular momentum j_*_, mass M_*_, and bulge fraction {beta}_*_ of normal galaxies of all morphological types are consistent with a simple model based on a linear superposition of independent disks and bulges. In this model, disks and bulges follow scaling relations of the form j_*_d{propto}M_*_d^{alpha}^ and j_*_b{propto}M_*_b^{alpha}^ with {alpha}=0.67+/-0.07 but offset from each other by a factor of 8+/-2 over the mass range 8.9<=log(M_*/M_{sun})<=11.8. Separate fits for disks and bulges alone give {alpha}=0.58+/-0.10 and {alpha}=0.83+/-0.16, respectively. This model correctly predicts that galaxies follow a curved 2D surface in the 3D space of log(j_*_), log(M_*_), and {beta}_*_. We find no statistically significant indication that galaxies with classical and pseudo bulges follow different relations in this space, although some differences are permitted within the observed scatter and the inherent uncertainties in decomposing galaxies into disks and bulges. As a byproduct of this analysis, we show that the j_*_-M_*_ scaling relations for disk-dominated galaxies from several previous studies are in excellent agreement with each other. In addition, we resolve some conflicting claims about the {beta}_*_ dependence of the j_*_-M_*_ scaling relations. The results presented here reinforce and extend our earlier suggestion that the distribution of galaxies with different {beta}_*_ in the j_*_-M_*_ diagram constitutes an objective, physically motivated alternative to subjective classification schemes such as the Hubble sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A149
- Title:
- J-PLUS Ly{alpha}-emitting candidates
- Short Name:
- J/A+A/643/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the photometric determination of the bright-end of the Ly{alpha} luminosity function (at L_Ly{alpha}_>~10^43.5^erg/s) within four redshifts windows ({Delta}z<0.16) in the interval 2.2<~z<~3.3. Our work is based on the Javalambre Photometric Local Universe Survey (J-PLUS) first data-release, which provides multiple narrow-band measurements over ~1000deg^2^, with limiting magnitude ~22. Theanalysis of high-z Ly{alpha}-emitting sources over such a wide area is unprecedented, and allows to select a total of ~14500 hyper-bright(L_Ly{alpha}_>10^43.3^erg/s) Ly{alpha}-emitting candidates. We test our selection with two spectroscopic follow-up programs at the GTC telescope,which confirm as line-emitting sources ~89% of the targets, with ~64% being genuine z~2.2 QSOs. We extend the 2.2<~z<~3.3 Ly{alpha} luminosity function for the first time above L_Ly{alpha}_~10^44^erg/s and down to densities of ~10^-8^Mpc^-3^. Our results unveil with high detail the Schechter exponential-decay of the brightest-end of the Ly{alpha} LF, complementing the power-law component of previous LF determinations at 43.3<~Log10(L_Ly{alpha}_/(erg/s))<~44. We measure {PHI}*=(3.33+/-0.19)x10^-6^, Log(L*)=44.65+/-0.65 and {alpha}=-1.35+/-0.84 as an average over the redshifts we probe. These values are significantly different than the typical Schechter parameters measured for the Ly{alpha} LF of high-z star-forming LAEs. This suggests that z>2 AGN/QSOs (likely dominant in our samples) are described by a structurally different LF than z>2 star-forming LAEs, namely with L*_QSOs_~100 L*_LAEs_ and {PHI}*_QSOs_~10^-3^{PHI}*_LAEs_. Finally, our method identifies very efficiently as high-z line-emitters sources without previous spectroscopic confirmation, currently classified as stars (~2000 objects in each redshift bin, on average). Assuming a large predominance of Ly{alpha}-emitting AGN/QSOs in our samples, this supports the scenario by which these are the most abundant class of z>~2 Ly{alpha} emitters at L_Ly{alpha}_>~10^43.3^erg/s.
- ID:
- ivo://CDS.VizieR/J/A+AS/98/393
- Title:
- 1Jy BL Lac Objects: Observational Data
- Short Name:
- J/A+AS/98/393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Direct imaging and spectroscopic data are reported for the complete sample of 34 BL Lac objects selected from the 1Jy source catalogue (see Cat. <VIII/5>). A short description of each individual object is given along with a general discussion of the features observed in the optical spectra, the optical morphologies, and the environments of the BL Lac objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/522/113
- Title:
- 1Jy IRAS galaxies optical spectroscopy
- Short Name:
- J/ApJ/522/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper discusses the optical spectroscopic properties of the IRAS 1Jy sample (f_60_>1Jy) of ultraluminous infrared galaxies (ULIGs: L_IR_>10^12^L_{sun}; H_0_=75km/s/Mpc and q_0_=0). One hundred eight of the 118 1Jy ULIGs have been observed at {Delta}{lambda}=8.3{AA} resolution over the wavelength range ~4500-8900{AA}. These data are combined with large, previously published sets of optical spectroscopic data of lower luminosity infrared galaxies to look for systematic trends with infrared luminosity over the luminosity range L_IR_~10^10.5^-10^13^L_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/399
- Title:
- K and evolutionary corrections
- Short Name:
- J/A+AS/122/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- K and evolutionary corrections are given for the E, Sa and Sc Hubble types for the following filters up to the redshift z=3: Johnson-Bessell & Brett photometric system: U, B, V, R, I, J, H, K filters Modified Thuan & Gunn system: gri filters Cousins system: Rc Ic filters Bj, Rf, In filters.
