- ID:
- ivo://CDS.VizieR/J/ApJ/750/168
- Title:
- Redshift survey in the Subaru GTO2deg^2^ field
- Short Name:
- J/ApJ/750/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a dense redshift survey in the foreground of the Subaru GTO2deg^2^ weak-lensing field (centered at 16:04:44+43:11'24 (2000) to assess the completeness and comment on the purity of massive halo identification in the weak-lensing map. The redshift survey (published here) includes 4541 galaxies; 4405 are new redshifts measured with the Hectospec on the MMT. Among the weak-lensing peaks with a signal to noise greater than 4.25, 2/3 correspond to individual massive systems; this result is essentially identical to the Geller et al. (2010ApJ...709..832G) test of the Deep Lens Survey (DLS) field F2. The Subaru map, based on images in substantially better seeing than the DLS, enables detection of less massive halos at fixed redshift as expected. We demonstrate that the procedure adopted by Miyazaki et al. (2002ApJ...580L..97M) for removing some contaminated peaks from the weak-lensing map improves agreement between the lensing map and the redshift survey in the identification of candidate massive systems.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/109/537
- Title:
- Redshift survey of faint galaxies
- Short Name:
- J/A+AS/109/537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJ/622/772
- Title:
- Redshift survey of submillimeter galaxies
- Short Name:
- J/ApJ/622/772
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectroscopic redshifts using the Keck I telescope for a sample of 76 submillimeter galaxies (SMGs), with a median 850{mu}m flux density of 5.7mJy, for which precise positions are available through their faint radio emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/124
- Title:
- Redshift survey of the nearby galaxy cluster A2107
- Short Name:
- J/ApJ/869/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the rotational motion of the galaxy cluster A2107 at redshift z=0.04 and its connection to nearby large-scale structures using a large amount of spectroscopic redshift data. By combining 978 new redshifts from the MMT/Hectospec observations with data in the literature, we construct a large sample of 1968 galaxies with measured redshifts at clustercentric radius R<60'. Our sample has high (80%) and spatially uniform completeness at r-band apparent magnitude m_r,Petro,0_<19.1. We first apply the caustic method to the sample and identify 285 member galaxies of A2107 at R<60'. Then the rotation amplitude and the position angle of the rotation axis are measured. We find that the member galaxies show strong global rotation at R<20' (v_rot_/{sigma}_v_~0.6) with a significance of >3.8{sigma}, which is confirmed by two independent methods. The rotation becomes weaker in outer regions. There are at least five filamentary structures that are connected to the cluster and that consist of known galaxy groups. These structures are smoothly connected to the cluster, which seem to be inducing the global rotation of the cluster through inflow of galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A15
- Title:
- Red supergiants around Stephenson 2
- Short Name:
- J/A+A/547/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several clusters of red supergiants have been discovered in a small region of the Milky Way close to the base of the Scutum-Crux Arm and the tip of the Long Bar. Population synthesis models indicate that they must be very massive to harbour so many supergiants. Amongst these clusters, Stephenson 2, with a core grouping of 26 red supergiants, is a strong candidate to be the most massive young cluster in the Galaxy. Stephenson 2 is located close to a region where a strong over-density of red supergiants had been found. We explore the actual cluster size and its possible connection to this over-density. Taking advantage of Virtual Observatory tools, we have performed a cross-match between the DENIS, USNO-B1 and 2MASS catalogues to identify candidate obscured luminous red stars around Stephenson 2, and in a control nearby region. More than 600 infrared bright stars fulfill our colour criteria, with the vast majority having a counterpart in the I band and >400 being sufficiently bright in I to allow observation with a 4-m class telescope. We observed a subsample of ~250 stars, using the multi-object, wide-field, fibre spectrograph AF2 on the WHT telescope in La Palma, obtaining intermediate-resolution spectroscopy in the 7500-9000{AA} range. We derived spectral types and luminosity classes for all these objects and measured their radial velocities.
5556. Red supergiants in M31
- ID:
- ivo://CDS.VizieR/J/ApJ/703/420
- Title:
- Red supergiants in M31
- Short Name:
- J/ApJ/703/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Red supergiants (RSGs) are a short-lived stage in the evolution of moderately massive stars (10-25M_{sun}_), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of RSGs in M31, the most metal-rich of the Local Group galaxies. We determine the physical properties of these stars using both moderate resolution spectroscopy and broadband V-K photometry. We find that on average the RSGs of our sample are variable in V by 0.5mag, smaller but comparable to the 0.9mag found for Magellanic Cloud (MC) RSGs. No such variability is seen at K, also in accord with what we know of Galactic and MC RSGs.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2867
- Title:
- Red supergiants in Magellanic Clouds
- Short Name:
- J/AJ/126/2867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the red supergiant (RSG) content of the SMC and LMC using multiobject spectroscopy on a sample of red stars previously identified by BVR CCD photometry. We obtained high-accuracy (<1km/s) radial velocities for 118 red stars seen toward the SMC and 167 red stars seen toward the LMC, confirming most of these (89% and 95%, respectively) as red supergiants. Spectral types were also determined for most of these RSGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/671/781
- Title:
- Red supergiants in Sct-Cru Galactic arm
- Short Name:
- J/ApJ/671/781
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the unprecedented red supergiant (RSG) population of a massive young cluster, located at the base of the Scutum-Crux Galactic arm. We identify candidate cluster RSGs based on 2MASS photometry and medium-resolution spectroscopy. With follow-up high-resolution spectroscopy, we use CO band-head equivalent width and high-precision radial velocity measurements to identify a core grouping of 26 physically associated RSGs-the largest such cluster known to date.
- ID:
- ivo://CDS.VizieR/J/AJ/161/79
- Title:
- Red supergiant stars in M31 and M33
- Short Name:
- J/AJ/161/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify red supergiants (RSGs) in our spiral neighbors M31 and M33 using near-IR (NIR) photometry complete to a luminosity limit of logL/L{odot}=4.0. Our archival survey data cover 5{deg}^2^ of M31, and 3{deg}^2^ for M33, and are likely spatially complete for these massive stars. Gaia is used to remove foreground stars, after which the RSGs can be separated from asymptotic giant branch (AGB) stars in the color-magnitude diagram. The photometry is used to derive effective temperatures and bolometric luminosities via MARCS stellar atmosphere models. The resulting H-R diagrams show superb agreement with the evolutionary tracks of the Geneva evolutionary group. Our census includes 6400 RSGs in M31 and 2850 RSGs in M33 within their Holmberg radii; by contrast, only a few hundred RSGs are known so far in the Milky Way. Our catalog serves as the basis for a study of the RSG binary frequency being published separately, as well as future studies relating to the evolution of massive stars. Here we use the matches between the NIR- selected RSGs and their optical counterparts to show that the apparent similarity in the reddening of OB stars in M31 and M33 is the result of Malmquist bias; the average extinction in M31 is likely higher than that of M33. As expected, the distribution of RSGs follows that of the spiral arms, while the much older AGB population is more uniformly spread across each galaxy's disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/53
- Title:
- Red supergiant stars in the LMC. I.
- Short Name:
- J/ApJ/727/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From previous samples of red supergiants (RSGs) by various groups, 191 objects are assembled to compose a large sample of RSG candidates in LMC. For 189 of them, the identity as an RSG is verified by their brightness and color indexes in several near- and mid-infrared bands related to the Two Micron All Sky Survey (2MASS) JHKs bands and the Spitzer/IRAC and Spitzer/MIPS bands. From the visual time-series photometric observations by the ASAS and MACHO projects which cover nearly 8-10 years, the period and amplitude of light variation are analyzed carefully using both the phase dispersion minimization and Period04 (Lenz, 2004CoAst.144...41L) methods.
