- ID:
- ivo://CDS.VizieR/J/ApJS/183/109
- Title:
- Cepheids in 3 host galaxies
- Short Name:
- J/ApJS/183/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first of two papers reporting measurements from a program to determine the Hubble constant to ~5% precision from a refurbished distance ladder. We present new observations of 110 Cepheid variables in the host galaxies of two recent Type Ia supernovae (SNe Ia), NGC 1309 and NGC 3021, using the Advanced Camera for Surveys on the Hubble Space Telescope (HST).
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- ID:
- ivo://CDS.VizieR/J/A+A/385/793
- Title:
- Cepheids in Magellanic Clouds. II.
- Short Name:
- J/A+A/385/793
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The analysis of CCD observations of ten new suspected second overtone mode Cepheids in the SMC does not confirm the nature of such stars; most of them appear to be first overtone mode Cepheids. A careful analysis of the OGLE best second overtone mode candidates and of the second overtone component of double mode Cepheids in SMC and LMC has been performed in order to clarify the possible effects of a resonance between pulsation modes. There are some indications that such a resonance is indeed operating in these pulsators. A brief discussion of the effects of blending on the light curve shape is also reported, and the usefulness of the Fourier parameters as mode discriminators is discussed. The observations were performed with the direct CCD camera at the Dutch 0.91m telescope of La Silla (ESO) during three runs in November 1997 (6 nights), July 1998 (12 nights) and October 1998 (15 nights). The CCD detector was the ESO chip No. 33, which is a TEK CCD with 512x512 pixels, pixel size of 27{mu}m and spatial resolution of 0.44", providing a small field of view of 3.77'x3.77'. 8 fields were selected in order to observe the ten second overtone candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/733/124
- Title:
- Cepheids in M101 observed with HST
- Short Name:
- J/ApJ/733/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival Hubble Space Telescope (HST)/Advanced Camera for Surveys V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal differential light curves from HST data. We discovered 827 Cepheids with periods between 3 and 80 days, the largest extragalactic sample of Cepheids observed with HST by a factor of two. With this large Cepheid sample, we find that the relative distance of M101 from the Large Magellanic Cloud is {Delta}{mu}_LMC_=10.63+/-0.04 (random) +/-0.06 (systematic) mag. If we use the geometrically determined maser distance to NGC 4258 as our distance anchor, the distance modulus of M101 is {mu}_0_=29.04+/-0.05 (random) +/-0.18 (systematic) mag or D=6.4+/-0.2 (random) +/-0.5 (systematic) Mpc. The uncertainty is dominated by the maser distance estimate (+/-0.15mag), which should improve over the next few years.
- ID:
- ivo://CDS.VizieR/J/AJ/156/130
- Title:
- Cepheids in M31 - PAndromeda Cepheid sample
- Short Name:
- J/AJ/156/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r_P1_, i_P1_, and g_P1_ bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the method developed by Kodric et al. (2013, , Cat. J/AJ/145/106), we identify Cepheids by using a three-dimensional parameter space of Fourier parameters of the Cepheid light curves combined with a color cut and other selection criteria. This is an unbiased approach to identify Cepheids and results in a homogeneous Cepheid sample. The period-luminosity relations obtained for our sample have smaller dispersions than in our previous work. We find a broken slope that we previously observed with HST data in Kodric et al. (2013, , Cat. J/AJ/145/106), albeit with a lower significance.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/2238
- Title:
- Cepheids in open clusters
- Short Name:
- J/MNRAS/434/2238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cepheids in open clusters (cluster Cepheids: CCs) are of great importance as zero-point calibrators of the Galactic Cepheid period-luminosity relationship (PLR). We perform an 8-dimensional all-sky census that aims to identify new bona-fide CCs and provide a ranking of membership confidence for known CC candidates according to membership probabilities. The probabilities are computed for combinations of known Galactic open clusters and classical Cepheid candidates, based on spatial, kinematic, and population-specific membership constraints. Data employed in this analysis are taken largely from published literature and supplemented by a year-round observing program on both hemispheres dedicated to determining systemic radial velocities of Cepheids. In total, we find 23 bona-fide CCs, 5 of which are candidates identified for the first time, including an overtone-Cepheid member in NGC 129. We discuss a subset of CC candidates in detail, some of which have been previously mentioned in the literature. Our results indicate unlikely membership for 7 Cepheids that have been previously discussed in terms of cluster membership. We furthermore revisit the Galactic PLR using our bona fide CC sample and obtain a result consistent with the recent calibration by Turner (2010). However, our calibration remains limited mainly by cluster uncertainties and the small number of long-period calibrators. In the near future, Gaia will enable our study to be carried out in much greater detail and accuracy, thanks to data homogeneity and greater levels of completeness.
- ID:
- ivo://CDS.VizieR/J/ApJ/699/539
- Title:
- Cepheids in SN-Ia host galaxies
- Short Name:
- J/ApJ/699/539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second of two papers reporting results from a program to determine the Hubble constant to ~5% precision from a refurbished distance ladder based on extensive use of differential measurements. Here we report observations of 240 Cepheid variables obtained with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) Camera 2 through the F160W filter on the Hubble Space Telescope (HST). The Cepheids are distributed across six recent hosts of Type Ia supernovae (SNe Ia) and the "maser galaxy" NGC 4258, allowing us to directly calibrate the peak luminosities of the SNe Ia from the precise, geometric distance measurements provided by the masers. New features of our measurement include the use of the same instrument for all Cepheid measurements across the distance ladder and homogeneity of the Cepheid periods and metallicities, thus necessitating only a differential measurement of Cepheid fluxes and reducing the largest systematic uncertainties in the determination of the fiducial SN Ia luminosity. In addition, the NICMOS measurements reduce the effects of differential extinction in the host galaxies by a factor of ~5 over past optical data. Combined with a greatly expanded set of 240 SNe Ia at z<0.1 which define their magnitude-redshift relation, we find H_0_=74.2+/-3.6km/s/Mpc, a 4.8% uncertainty including both statistical and systematic errors.
- ID:
- ivo://CDS.VizieR/J/A+A/440/487
- Title:
- Cepheids in the young LMC cluster NGC 1866
- Short Name:
- J/A+A/440/487
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new near-IR light curves for six Cepheids in the young blue LMC cluster NGC 1866 as well as high precision radial velocity curves for ten Cepheids in NGC 1866 and two in NGC 2031. For the six Cepheids in NGC 1866 with new J and K light curves we determine distances and absolute magnitudes by applying the near-IR surface brightness method. We find that the formal error estimates on the derived distances are underestimated by about a factor of two. We find excellent agreement between the absolute magnitudes for the low metallicity LMC Cepheids with the Period-Luminosity (P-L) relation determined by the near-IR surface brightness (ISB) method for Galactic Cepheids suggesting that the slope of the P-L relations for low metallicity and solar metallicity samples could be very similar in contrast to other recent findings. Still there appears to be significant disagreement between the observed slopes of the OGLE based apparent P-L relations in the LMC and the slopes derived from ISB analysis of Galactic Cepheids, and by inference for Magellanic Cloud Cepheids, indicating a possible intrinsic problem with the ISB method itself. Resolving this problem could reaffirm the P-L relation as the prime distance indicator applicable as well to metallicities significantly different from the LMC value.
- ID:
- ivo://nasa.heasarc/cepaxmm
- Title:
- Cepheus A SFR XMM-Newton X-Ray Point Source Catalog
- Short Name:
- CEPAXMM
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Cepheus A is a star formation region (SFR) at a distance of ~ 730 pc consisting of two main H II regions, Cep A East and Cep A West. Cep A was observed with the EPIC cameras of the XMM-Newton observatory on 2003 August 23 for 43.9ks. In this observation, X-rays from both components of Cep A, East and West, were discovered by XMM-Newton, as well as from the Herbig-Haro object HH 168, which joins the ranks of other energetic H-H objects that are sources of temperature T >= 10<sup>6</sup> K X-ray emission. A total of 102 distinct X-ray sources were detected in this 44 ks observation, many presumed to be pre-main-sequence stars on the basis of the reddening of their optical and IR counterparts, the latter being found by matching the positions of the 102 X-ray sources with objects in the USNO-B1.0 (Monet et al. 2003, AJ, 125, 984) and Two Micron All Sky Survey (2MASS) catalogs using a 2.5" matching radius. The authors performed source detection on all the XMM-Newton data in two energy bands: 0.2 - 1 keV ("soft") and 1 - 10 keV ("hard"). They detected 24 soft sources and 85 hard sources. Seven of the sources appear in both bands, where the criterion for a match between the bands is a positional offset of < 2.5 arcseconds. Thus, the total number of distinct X-ray sources detected (and listed in this table) is 102. This table was created by the HEASARC in July 2007 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/626/272">CDS Catalog J/ApJ/626/272</a> file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+A/602/A8
- Title:
- Cepheus E CO, OH and OI spectra
- Short Name:
- J/A+A/602/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Protostellar jets and outflows are key features of the star-formation process, and primary processes of the feedback of young stars on the interstellar medium. Understanding the underlying shocks is necessary to explain how jet and outflow systems are launched, and to quantify their chemical and energetic impacts on the surrounding medium. We performed a high-spectral resolution study of the [OI]63um emission in the outflow of the intermediate-mass Class 0 protostar Cep E-mm. The goal is to determine the structure of the outflow, to constrain the chemical conditions in the various components, and to understand the nature of the underlying shocks, thus probing the origin of the mass-loss phenomenon. We present observations of the OI ^3^P_1_ -> ^3^P_2_, OH between ^2^{Pi}_1/2_ J=3/2 and J=1/2 at 1837.8GHz, and CO (16-15) lines with the GREAT receiver onboard SOFIA towards three positions in the Cep E protostellar outflow: Cep E-mm (the driving protostar), Cep E-BI (in the southern lobe), and Cep E-BII (the terminal position in the southern lobe).
- ID:
- ivo://CDS.VizieR/J/ApJS/115/59
- Title:
- Cepheus flare molecular clouds
- Short Name:
- J/ApJS/115/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of an objective prism Schmidt survey are combined with IRAS survey data in order to assess the star-forming activity in the Cepheus Flare, a nearby giant molecular cloud complex at ~15{deg} above the Galactic equator. The distribution of absorbing matter along the line of sight was also studied. The Wolf diagrams, displaying the cumulative distribution of field star distance moduli, show that the interstellar matter in this region is concentrated at three characteristic distances: 200, 300, and 450pc. The three components, though partly overlapping, can be separated along the Galactic latitude. Within the area of the Cepheus Flare, distances are determined for 14 Lynds dark clouds and for some other clouds.