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- ID:
- ivo://CDS.VizieR/II/43
- Title:
- K-line photometry of Southern A stars
- Short Name:
- II/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photoelectric measurements of the strength of the Calcium K-line has been extended by 223 stars of predominantly southern or equatorial declinations which are well distributed in right ascension. This has expanded the existent list to 369 field stars for which a k-index is available, including many more Am stars. All available k-index data for field stars are presented here.
- ID:
- ivo://CDS.VizieR/II/44
- Title:
- K-Line photometry of stars in Population I clusters
- Short Name:
- II/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric photometry of the K-line of calcium has been performed for the A stars of five open clusters (Hyades, Pleiades, IC 2391, IC 2602, and NGC 6475) and one association (Orion). All observations were carried out simultaneously with the field stars measurements in Paper II (II/43), with the 16-inch (40cm) and 36-inch (91cm) telescopes of the Cerro Tololo Inter-American Observatory, between May 1969 and January 1970.
- ID:
- ivo://CDS.VizieR/J/A+A/323/139
- Title:
- K magnitude of Pleiades low-mass binaries
- Short Name:
- J/A+A/323/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table provides the list of stars observed but not resolved during the diffraction-limited survey of G and K Pleiades dwarfs. Previously known binaries, either photometric or spectroscopic, are referenced.
- ID:
- ivo://CDS.VizieR/J/MNRAS/355/20
- Title:
- K magnitudes of 74MHz radio sources
- Short Name:
- J/MNRAS/355/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present near-infrared K-band imaging of a sample of ultra-steep-spectrum (USS) radio sources selected at 74-MHz. The dual selection criteria of low frequency and USS mean that we should be sensitive to the highest-redshift (z>5) radio galaxies. We have obtained K-band magnitudes for all of the objects in our sample of 26 and discuss the properties of each.
- ID:
- ivo://CDS.VizieR/J/A+A/469/459
- Title:
- K magnitudes of N159-5 (LMC)
- Short Name:
- J/A+A/469/459
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution near-infrared imaging of the compact HII region N159-5 and its immediate environment in the giant-star forming region N159 in the LMC. N159-5 was observed at high spatial resolution ~0.11"-0.25" in the K-band using the ESO Very Large Telescope UT4 (VLT), equipped with the NAOS adaptive optics system. Our data reveal that N159-5 has a complex morphology formed mainly by two wings and probably a single central bright star, embedded in diffuse emission of ~4.5" diameter. A remarkable embedded tight cluster of approximatively the same size, containing at least 38 faint stars coinciding with N159-5, is also detected. Such clusters can be found in galactic HII regions like the star-forming regions SH2 269 or M42. At the location of the radio peak, especially in the bright western wing, this cluster is rich in stars. Spectroscopic observations reveal that the diffuse region is constituted mainly of dust continuum and that the bright star #2-55 could be of type O8 V. A comparison with the radio observation flux of N159-5 published in the literature seems to show that the bright star #2-55 is not the only ionization source of N159-5. Towards N159-5 molecular H_2_ emission is detected. A model of the region is proposed.
- ID:
- ivo://CDS.VizieR/J/A+A/440/121
- Title:
- K magnitudes of OB stars in UCHIIs
- Short Name:
- J/A+A/440/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained high resolution (R=10000) K-band spectra of candidate young massive stars deeply embedded in (ultra-) compact HII regions (UCHIIs). These objects were selected from a near-infrared survey of 44 fields centered on IRAS sources with UCHII colours. Often, the near-infrared counterpart of the IRAS source is a young embedded cluster hosting massive stars. In these clusters, three types of objects are identified. The first type (38 objects) consists of "naked" OB stars whose K-band spectra are dominated by photospheric emission. We classify the K-band spectra of the OB-type cluster members using near-infrared classification criteria. A few of them have a very early (O3-O4 V) spectral type, consistent with a young age of the embedded clusters. The spectral classification provides an important constraint on the distance to the embedded cluster.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/1195
- Title:
- KMOS AGN Survey at High redshift (KASHz)
- Short Name:
- J/MNRAS/456/1195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the KMOS (K-band Multi-Object Spectrograph) AGN (active galactic nuclei) Survey at High redshift (KASHz), a VLT/KMOS integral-field spectroscopic (IFS) survey of z>~0.6 AGN. We present galaxy-integrated spectra of 89 X-ray AGN (L_2-10keV_= 10^42^-10^45^erg/s), for which we observed [OIII] (z~1.1-1.7) or H{alpha} emission (z~0.6-1.1). The targets have X-ray luminosities representative of the parent AGN population and we explore the emission-line luminosities as a function of X-ray luminosity. For the [OIII] targets, ~50 per cent have ionized gas velocities indicative of gas that is dominated by outflows and/or highly turbulent material (i.e. overall line widths >~600km/s). The most luminous half (i.e. L_X_>6x10^43^erg/s) have a>~2 times higher incidence of such velocities. On the basis of our results, we find no evidence that X-ray obscured AGN are more likely to host extreme kinematics than unobscured AGN. Our KASHzsample has a distribution of gas velocities that is consistent with a luminosity-matched sample of z<0.4 AGN. This implies little evolution in the prevalence of ionized outflows, for a fixed AGN luminosity, despite an order-of-magnitude decrease in average star formation rates over this redshift range. Furthermore, we compare our H{alpha} targets to a redshift-matched sample of star-forming galaxies and despite a similar distribution of H{alpha} luminosities and likely star formation rates, we find extreme ionized gas velocities are up to ~10 times more prevalent in the AGN-host galaxies. Our results reveal a high prevalence of extreme ionized gas velocities in high-luminosity X-ray AGN and imply that the most powerful ionized outflows in high-redshift galaxies are driven by AGN activity.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A34
- Title:
- KMOS O-type star detection in Tr 16-SE
- Short Name:
- J/A+A/648/A34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carina Nebula harbors a large population of high-mass stars, including at least 75 O-type and Wolf-Rayet (WR) stars, but the current census is not complete since further high-mass stars may be hidden in or behind the dense dark clouds that pervade the association. With the aim of identifying optically obscured O- and early B-type stars in the Carina Nebula, we performed the first infrared spectroscopic study of stars in the optically obscured stellar cluster Tr 16-SE, located behind a dark dust lane south of {eta} Car. We used the integral-field spectrograph KMOS at the ESO VLT to obtain H- and K-band spectra with a resolution of R~4000 ({Delta}{lambda}~5{AA}) for 45 out of the 47 possible OB candidate stars in Tr 16-SE, and we derived spectral types for these stars. We find 15 stars in Tr 16-SE with spectral types between O5 and B2 (i.e. high-mass stars with M>=8M_{sun}_), only two of which were known before. An additional nine stars are classified as (Ae)Be stars, i.e. intermediate-mass pre-main sequence stars, and most of the remaining targets show clear signatures of being late-type stars and are thus most likely foreground stars or background giants unrelated to the Carina Nebula. Our estimates of the stellar luminosities suggest that nine of the 15 O- and early B-type stars are members of Tr 16-SE, whereas the other six seem to be background objects. Our study increases the number of spectroscopically identified high-mass stars (M>=8M_{sun}_) in Tr 16-SE from two to nine and shows that Tr 16-SE is one of the larger clusters in the Carina Nebula. Our identification of three new stars with spectral types between O5 and O7 and four new stars with spectral types O9 to B1 significantly increases the number of spectroscopically identified O-type stars in the Carina Nebula.
- 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.