- ID:
- ivo://CDS.VizieR/J/MNRAS/473/4130
- Title:
- M31 center emission-line point-like sources
- Short Name:
- J/MNRAS/473/4130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed description of the wavelength, astrometric and photometric calibration plan for SITELLE, the imaging Fourier transform spectrometer attached to the Canada-France-Hawaii telescope, based on observations of a red (647-685nm) data cube of the central region (11'x11') of the Andromeda galaxy. The first application, presented in this paper, is a radial-velocity catalogue (with uncertainties of ~2-6km/s) of nearly 800 emission-line point-like sources, including ~450 new discoveries. Most of the sources are likely planetary nebulae, although we also detect five novae (having erupted in the first 8 months of 2016) and one new supernova remnant candidate.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/805/143
- Title:
- MC2: redshift analysis of CIZA J2242.8+5301
- Short Name:
- J/ApJ/805/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- X-ray and radio observations of CIZA J2242.8+5301 suggest that it is a major cluster merger. Despite being well studied in the X-ray and radio, little has been presented on the cluster structure and dynamics inferred from its galaxy population. We carried out a deep (i<25) broadband imaging survey of the system with Subaru SuprimeCam (g and i bands) and the Canada-France-Hawaii Telescope (r band), as well as a comprehensive spectroscopic survey of the cluster area (505 redshifts) using Keck DEep Imaging Multi-Object Spectrograph. We use these data to perform a comprehensive galaxy/redshift analysis of the system, which is the first step to a proper understanding of the geometry and dynamics of the merger, as well as using the merger to constrain self-interacting dark matter. We find that the system is dominated by two subclusters of comparable richness with a projected separation of 6.9'_-0.5_^+0.7^ (1.3_-0.10_^+0.13^Mpc). We find that the north and south subclusters have similar redshifts of z~0.188 with a relative line-of-sight (LOS) velocity difference of 69+/-190km/s. We also find that north and south subclusters have velocity dispersions of 1160_-90_^+100^ and 1080_-70_^+100^km/s, respectively. These correspond to masses of 16.1_-3.3_^+4.6^x10^14^ and 13.0_-2.5_^+4.0^x10^14^M_{Sun}_, respectively. While velocity dispersion measurements of merging clusters can be biased, we believe the bias in this system to be minor due to the large projected separation and nearly plane-of-sky merger configuration. We also find that the cDs of the north and south subclusters are very near their subcluster centers, in both projection (55 and 85kpc, respectively) and normalized LOS velocity (|{Delta}v|/{sigma}_v_=0.43+/-0.13 and 0.21+/-0.12 for the north and south, respectively). CIZA J2242.8+5301 is a relatively clean dissociative cluster merger with near 1:1 mass ratio, which makes it an ideal merger for studying merger-associated physical phenomena.
- ID:
- ivo://CDS.VizieR/J/A+A/393/167
- Title:
- Mean Spectra for upper AGB stars
- Short Name:
- J/A+A/393/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Provided are average spectra extending from 510 to 2490nm for: - Oxygen rich, optically visible LPVs (temperature sequence based on the colour I-K); - Carbon rich, optically visible LPVs (temperature sequence based on the colour R-H, and C/O sequence); - Oxygen rich, dust-enshrouded LPVs (reddened versions of the coolest optically visible average); - Carbon rich, dust-enshrouded LPVs (reddened versions of the coolest optically visible average).
- ID:
- ivo://CDS.VizieR/J/ApJ/853/87
- Title:
- MEGaSaURA. II. Stacked spectra
- Short Name:
- J/ApJ/853/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We stack the rest-frame ultraviolet spectra of N=14 highly magnified gravitationally lensed galaxies at redshifts 1.6<z<3.6. The resulting new composite spans 900<{lambda}_rest_<3000{AA}, with a peak signal-to-noise ratio (S/N) of 103 per spectral resolution element (~100km/s). It is the highest S/N, highest spectral resolution composite spectrum of z~2-3 galaxies yet published. The composite reveals numerous weak nebular emission lines and stellar photospheric absorption lines that can serve as new physical diagnostics, particularly at high redshift with the James Webb Space Telescope (JWST). We report equivalent widths to aid in proposing for and interpreting JWST spectra. We examine the velocity profiles of strong absorption features in the composite, and in a matched composite of z~0 COS/HST galaxy spectra. We find remarkable similarity in the velocity profiles at z~0 and z~2, suggesting that similar physical processes control the outflows across cosmic time. While the maximum outflow velocity depends strongly on ionization potential, the absorption-weighted mean velocity does not. As such, the bulk of the high- ionization absorption traces the low-ionization gas, with an additional blueshifted absorption tail extending to at least -2000km/s. We interpret this tail as arising from the stellar wind and photospheres of massive stars. Starburst99 models are able to replicate this high-velocity absorption tail. However, these theoretical models poorly reproduce several of the photospheric absorption features, indicating that improvements are needed to match observational constraints on the massive stellar content of star-forming galaxies at z~2.
- ID:
- ivo://CDS.VizieR/J/AJ/155/104
- Title:
- MEGaSaURA. I. The sample and the spectra
- Short Name:
- J/AJ/155/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce Project MEGaSaURA: the Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas. MEGaSaURA comprises medium-resolution, rest-frame ultraviolet spectroscopy of N=15 bright gravitationally lensed galaxies at redshifts of 1.68<z<3.6, obtained with the MagE spectrograph on the Magellan telescopes. The spectra cover the observed-frame wavelength range 3200<{lambda}_o_<8280{AA}; the average spectral resolving power is R=3300. The median spectrum has a signal-to- noise ratio (S/N)=21 per resolution element at 5000{AA}. As such, the MEGaSaURA spectra have superior S/N and wavelength coverage compared to what COS/HST provides for starburst galaxies in the local universe. This paper describes the sample, the observations, and the data reduction. We compare the measured redshifts for the stars, the ionized gas as traced by nebular lines, and the neutral gas as traced by absorption lines; we find the expected bulk outflow of the neutral gas, and no systemic offset between the redshifts measured from nebular lines and the redshifts measured from the stellar continuum.
- ID:
- ivo://CDS.VizieR/J/AJ/159/282
- Title:
- Membership in Ophiuchus & Upper Scorpius complex
- Short Name:
- J/AJ/159/282
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a survey for new members of the Ophiuchus cloud complex using high-precision astrometry from the second data release of Gaia, proper motions measured with multi-epoch images from the Spitzer Space Telescope, and color-magnitude diagrams constructed with photometry from various sources. Through spectroscopy of candidates selected with those data, we have identified 155 new young stars. Based on available measurements of kinematics, we classify 102, 47, and 6 of those stars as members of Ophiuchus, Upper Sco, and other populations in Sco-Cen, respectively. We have also assessed the membership of all other stars in the vicinity of Ophiuchus that have spectroscopic evidence of youth from previous studies, arriving at a catalog of 373 adopted members of the cloud complex. For those adopted members, we have compiled mid-infrared photometry from Spitzer and the Wide-field Infrared Survey Explorer and have used mid-infrared colors to identify and classify circumstellar disks. We find that 210 of the members show evidence of disks, including 48 disks that are in advanced stages of evolution. Finally, we have estimated the relative median ages of the populations near the Ophiuchus clouds and the surrounding Upper Sco association using absolute K-band magnitudes (MK) based on Gaia parallaxes. If we adopt an age 10Myr for Upper Sco, then the relative values of MK imply median ages of ~2Myr for L1689 and embedded stars in L1688, 3-4Myr for low-extinction stars near L1688, and ~6Myr for the group containing {rho}Oph.
- ID:
- ivo://CDS.VizieR/J/ApJ/832/87
- Title:
- Members of the young open cluster IC 2395
- Short Name:
- J/ApJ/832/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new deep UBVRI images and high-resolution multi-object optical spectroscopy of the young (~6-10Myr old), relatively nearby (800pc) open cluster IC 2395. We identify nearly 300 cluster members and use the photometry to estimate their spectral types, which extend from early B to middle M. We also present an infrared imaging survey of the central region using the IRAC and MIPS instruments on board the Spitzer Space Telescope, covering the wavelength range from 3.6 to 24{mu}m. Our infrared observations allow us to detect dust in circumstellar disks originating over a typical range of radii from ~0.1 to ~10 au from the central star. We identify 18 Class II, 8 transitional disk, and 23 debris disk candidates, respectively, 6.5%, 2.9%, and 8.3% of the cluster members with appropriate data. We apply the same criteria for transitional disk identification to 19 other stellar clusters and associations spanning ages from ~1 to ~18Myr. We find that the number of disks in the transitional phase as a fraction of the total with strong 24{mu}m excesses ([8]-[24]>=1.5) increases from (8.4+/-1.3)% at ~3Myr to (46+/-5)% at ~10Myr. Alternative definitions of transitional disks will yield different percentages but should show the same trend.
- ID:
- ivo://CDS.VizieR/J/ApJ/838/11
- Title:
- Member stars in the MW satellite Tucana III
- Short Name:
- J/ApJ/838/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Magellan/IMACS spectroscopy of the recently discovered Milky Way satellite Tucana III (Tuc III). We identify 26 member stars in Tuc III from which we measure a mean radial velocity of v_hel_=-102.3+/-0.4(stat.)+/-2.0(sys.)km/s, a velocity dispersion of 0.1_-0.1_^+0.7^km/s, and a mean metallicity of [Fe/H]=-2.42_-0.08_^+0.07^. The upper limit on the velocity dispersion is {sigma}<1.5km/s at 95.5% confidence, and the corresponding upper limit on the mass within the half-light radius of Tuc III is 9.0x10^4^M_{sun}_. We cannot rule out mass-to-light ratios as large as 240M_{sun}_/L_{sun}_ for Tuc III, but much lower mass-to-light ratios that would leave the system baryon-dominated are also allowed. We measure an upper limit on the metallicity spread of the stars in Tuc III of 0.19dex at 95.5% confidence. Tuc III has a smaller metallicity dispersion and likely a smaller velocity dispersion than any known dwarf galaxy, but a larger size and lower surface brightness than any known globular cluster. Its metallicity is also much lower than those of the clusters with similar luminosity. We therefore tentatively suggest that Tuc III is the tidally stripped remnant of a dark matter-dominated dwarf galaxy, but additional precise velocity and metallicity measurements will be necessary for a definitive classification. If Tuc III is indeed a dwarf galaxy, it is one of the closest external galaxies to the Sun. Because of its proximity, the most luminous stars in Tuc III are quite bright, including one star at V=15.7 that is the brightest known member star of an ultra-faint satellite.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/39
- Title:
- Merging galaxy cluster deep observations
- Short Name:
- J/ApJS/240/39
- Date:
- 18 Jan 2022 14:59:05
- Publisher:
- CDS
- Description:
- Multi-band photometric and multi-object spectroscopic surveys of merging galaxy clusters allow for the characterization of the distributions of constituent DM and galaxy populations, constraints on the dynamics of the merging subclusters, and an understanding of galaxy evolution of member galaxies. We present deep photometric observations from Subaru/SuprimeCam and a catalog of 4431 spectroscopic galaxies from Keck/DEIMOS observations of 29 merging galaxy clusters ranging in redshift from z=0.07 to 0.55. The ensemble is compiled based on the presence of radio relics, which highlight cluster-scale collisionless shocks in the intracluster medium. Together with the spectroscopic and photometric information, the velocities, timescales, and geometries of the respective merging events may be tightly constrained. In this preliminary analysis, the velocity distributions of 28 of the 29 clusters are shown to be well fit by single Gaussians. This indicates that radio-relic mergers largely occur transverse to the line of sight and/or near-apocenter. In this paper, we present our optical and spectroscopic surveys, preliminary results, and a discussion of the value of radio-relic mergers for developing accurate dynamical models of each system.
- ID:
- ivo://CDS.VizieR/J/A+A/485/571
- Title:
- Metallicities & activities of southern stars
- Short Name:
- J/A+A/485/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from high-resolution spectroscopic measurements to determine metallicities and activities of bright stars in the southern hemisphere.