- ID:
- ivo://CDS.VizieR/J/MNRAS/474/5076
- Title:
- KMOS Redshift One Spectroscopic Survey
- Short Name:
- J/MNRAS/474/5076
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the velocity dispersion properties of 472 z~0.9 star-forming galaxies observed as part of the KMOS Redshift One Spectroscopic Survey (KROSS). The majority of this sample is rotationally dominated (83+/-5 per cent with vC/{sigma}0>1) but also dynamically hot and highly turbulent. After correcting for beam smearing effects, the median intrinsic velocity dispersion for the final sample is {sigma}0=43.2+/-0.8km/s with a rotational velocity to dispersion ratio of vC/{sigma}0=2.6+/-0.1. To explore the relationship between velocity dispersion, stellar mass, star formation rate, and redshift, we combine KROSS with data from the SAMI survey (z~0.05) and an intermediate redshift MUSE sample (z~0.5). Whilst there is, at most, a weak trend between velocity dispersion and stellar mass, at fixed mass there is a strong increase with redshift. At all redshifts, galaxies appear to follow the same weak trend of increasing velocity dispersion with star formation rate. Our results are consistent with an evolution of galaxy dynamics driven by discs that are more gas rich, and increasingly gravitationally unstable, as a function of increasing redshift. Finally, we test two analytic models that predict turbulence is driven by either gravitational instabilities or stellar feedback. Both provide an adequate description of the data, and further observations are required to rule out either model.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/594/A77
- Title:
- KMOS star-forming galaxies Halpha data cubes
- Short Name:
- J/A+A/594/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of the evolution of star-forming galaxies requires the determination of accurate kinematics and scaling relations out to high redshift. In this paper we select a sample of 18 galaxies at z~1, observed in the H{alpha} emission-line with KMOS, to derive accurate kinematics using a novel 3D analysis technique. We use the new code 3DBarolo that models the galaxy emission directly in the 3D observational space, without the need to extract kinematic maps. This technique's major advantage is that it is not affected by beam smearing and thus it enables the determination of rotation velocity and intrinsic velocity dispersion, even at low spatial resolution. We find that: 1) the rotation curves of these z~1 galaxies rise very steeply within few kiloparsecs and remain flat out to the outermost radius and 2) the H{alpha} velocity dispersions are low, ranging from 15 to 40km/s, which leads to V/{sigma}=3-10. These characteristics are similar to those of disc galaxies in the local Universe. Finally, we also report no significant evolution of the stellar-mass Tully-Fisher relation. Our results show that disc galaxies are kinematically mature and rotation-dominated already at z~1.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A2
- Title:
- KMOS view of the Galactic centre. I.
- Short Name:
- J/A+A/584/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Galactic centre hosts a crowded, dense nuclear star cluster with a half-light radius of 4pc. Most of the stars in the Galactic centre are cool late-type stars, but there are also >=100 hot early-type stars in the central parsec of the Milky Way. These stars are only 3-8Myr old. Our knowledge of the number and distribution of early-type stars in the Galactic centre is incomplete. Only a few spectroscopic observations have been made beyond a projected distance of 0.5pc of the Galactic centre. The distribution and kinematics of early-type stars are essential to understand the formation and growth of the nuclear star cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/158/20
- Title:
- K-M stars of class I candidate RSGs in Gaia DR2
- Short Name:
- J/AJ/158/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate individual distances and luminosities of a sample of 889 nearby candidate red supergiants (RSGs) with reliable parallaxes ({omega}/{sigma}_{omega}_>4 and RUWE<2.7) from Gaia Data Release 2 (DR2, Cat. I/345). The sample was extracted from the historical compilation of spectroscopically derived spectral types by Skiff (Cat. B/mk), and consists of K-M stars that are listed with class I at least once. The sample includes well-known RSGs from Humphreys (1978ApJS...38..309H), Elias et al. (1985ApJS...57...91E), Jura & Kleinmann (1990ApJS...73..769J), and Levesque et al. (2005ApJ...628..973L). Infrared and optical measurements from the Two Micron All Sky Survey, Catalog of Infrared Observations (CIO), Midcourse Space Experiment, Wide-field Infrared Survey Explorer, MIPSGAL, Galactic Legacy Infrared Midplane Extraordinaire (GLIMPSE), and The Naval Observatory Merged Astrometric Dataset catalogs allow us to estimate the stellar bolometric magnitudes. We analyze the stars in the luminosity versus effective temperature plane and confirm that 43 sources are highly probably RSGs with M_bol_< -7.1 mag. Of the stars in the sample, 43% have masses >7 M_{sun}_. Another ~30% of the sample consists of giant stars.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A53
- Title:
- Kn 26, a new quadrupolar planetary nebula
- Short Name:
- J/A+A/551/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has only recently been recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time lapse between the ejection of the two pairs of bipolar lobes is much shorter than their dynamical ages, implying a rapid change in the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as for type II PNe) and a high helium abundance (as for type I PNe), although not atypical among symbiotic stars. Such an anomalous chemical composition may have resulted from the curtailment of the time in the asymptotic giant branch by the evolution of the progenitor star through a common envelope phase.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A100
- Title:
- K2 new planetary and EB candidates
- Short Name:
- J/A+A/594/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With only two functional reaction wheels, Kepler cannot maintain stable pointing at its original target field and has entered a new mode of observation called K2. We describe a new pipeline to reduce K2 pixel files into light curves that are later searched for transit like features. Our method is based on many years of experience in planet hunting for the CoRoT mission. Owing to the unstable pointing, K2 light curves present systematics that are correlated with the target position in the ccd. Therefore, our pipeline also includes a decorrelation of this systematic noise. Our pipeline is optimised for bright stars for which spectroscopic follow-up is possible. We achieve a maximum precision on 6 hours of 6 ppm. The decorrelated light curves are searched for transits with an adapted version of the CoRoT alarm pipeline. We present 172 planetary candidates and 327 eclipsing binary candidates from campaigns 1, 2, 3, 4, 5, and 6 of K2. Both the planetary candidates and eclipsing binary candidates lists are made public to promote follow-up studies. The light curves will also be available to the community.
- ID:
- ivo://CDS.VizieR/J/ApJ/866/139
- Title:
- Knots in the deep [FeII]+[SiI] image of the SNR Cas A
- Short Name:
- J/ApJ/866/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a long-exposure (~10hr), narrowband image of the supernova (SN) remnant Cassiopeia A (Cas A) centered at 1.644{mu}m emission. The passband contains [FeII] 1.644{mu}m and [SiI] 1.645{mu}m lines, and our "deep [FeII]+[SiI] image" provides an unprecedented panoramic view of Cas A, showing both shocked and unshocked SN ejecta, together with shocked circumstellar medium at subarcsecond (~0.7" or 0.012pc) resolution. The diffuse emission from the unshocked SN ejecta has a form of clumps, filaments, and arcs, and their spatial distribution correlates well with that of the Spitzer [SiII] infrared emission, suggesting that the emission is likely due to [SiI] not [FeII] as in shocked material. The structure of the optically invisible western area of Cas A is clearly seen for the first time. The area is filled with many quasi-stationary flocculi (QSFs) and fragments of the disrupted ejecta shell. We identified 309 knots in the deep [FeII]+[SiI] image and classified them into QSFs and fast-moving knots (FMKs). The comparison with previous optical plates indicates that the lifetime of most QSFs is >~60yr. The total H+He mass of QSFs is ~0.23M_{sun}_, implying that the mass fraction of dense clumps in the progenitor's mass ejection immediately prior to the SN explosion is about 4%-6%. FMKs in the deep [FeII]+[SiI] image mostly correspond to S-rich ejecta knots in optical studies, while those outside the southeastern disrupted ejecta shell appear Fe-rich. The mass of the [FeII] line emitting, shocked dense Fe ejecta is ~3x10^-5^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A101
- Title:
- Known Galactic field Blazhko stars
- Short Name:
- J/A+A/549/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A list of known Galactic field stars exhibiting Blazhko effect containing 242 stars is presented. All the entries including their designations, positions, pulsation, and Blazhko periods were collected from the available literature. The actual values of parameters are given.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/401
- Title:
- Known LT dwarfs in the Gaia DR1
- Short Name:
- J/MNRAS/469/401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify and investigate known ultracool stars and brown dwarfs that are being observed or indirectly constrained by the Gaia mission. These objects will be the core of the Gaia ultracool dwarf sample composed of all dwarfs later than M7 that Gaia will provide direct or indirect information on. We match known L and T dwarfs to the Gaia first data release, the Two Micron All Sky Survey and the Wide-field Infrared Survey Explorer AllWISE survey and examine the Gaia and infrared colours, along with proper motions, to improve spectral typing, identify outliers and find mismatches. There are 321 L and T dwarfs observed directly in the Gaia first data release, of which 10 are later than L7. This represents 45 per cent of all the known LT dwarfs with estimated GaiaG magnitudes brighter than 20.3mag. We determine proper motions for the 321 objects from Gaia and the Two Micron All Sky Survey positions. Combining the Gaia and infrared magnitudes provides useful diagnostic diagrams for the determination of L and T dwarf physical parameters. We then search the Tycho-Gaia astrometric solution, Gaia first data release subset, to find any objects with common proper motions to known L and T dwarfs and a high probability of being related. We find 15 new candidate common proper motion systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/6
- Title:
- Known members of Orion A with Gaia DR2 data
- Short Name:
- J/ApJ/884/6
- Date:
- 04 Dec 2021
- Publisher:
- CDS
- Description:
- The star-forming region of the Orion Nebula (ONC) is ideal to study the stellar dynamics of young stars in a clustered environment. Using Gaia DR2 we search for pre-main sequence stars with unusually high proper motions that may be representative of a dynamical ejection from unstable young triple systems or other close three-body encounters. We identify 26 candidate stars that are likely to have had such an encounter in the last 1Myr. Nine of these stars could be traced back to the densest central-most region of the ONC, the Trapezium, while five others have likely interactions with other OB-type stars in the cluster. Seven stars originate from other nearby populations within the Orion Complex that coincidentally scattered toward the ONC. A definitive point of origin cannot be identified for the remaining sources. These observations shed light on the frequency of the ejection events in young clusters.