- ID:
- ivo://CDS.VizieR/J/AJ/153/149
- Title:
- Broadband photometry of Neptune from K2
- Short Name:
- J/AJ/153/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report here on our search for excess power in photometry of Neptune collected by the K2 mission that may be due to intrinsic global oscillations of the planet Neptune. To conduct this search, we developed new methods to correct for instrumental effects such as intrapixel variability and gain variations. We then extracted and analyzed the time-series photometry of Neptune from 49 days of nearly continuous broadband photometry of the planet. We find no evidence of global oscillations and place an upper limit of ~5ppm at 1000{mu}Hz for the detection of a coherent signal. With an observed cadence of 1 minute and a point-to-point scatter of less than 0.01%, the photometric signal is dominated by reflected light from the Sun, which is in turn modulated by atmospheric variability of Neptune at the 2% level. A change in flux is also observed due to the increasing distance between Neptune and the K2 spacecraft and the solar variability with convection-driven solar p modes present.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/384/504
- Title:
- Broadband polarimetry of novae in outburst
- Short Name:
- J/A+A/384/504
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present broadband optical polarimetry of the classical novae V705 Cas, V4362 Sgr, V2313 Oph and BY Cir in outburst. The data indicate that, in all cases, there is an intrinsic component of polarization and in some cases the variability is very rapid, on a time-scale ~1day. In the case of V705 Cas, we suggest that the origin of the intrinsic component may lie in the clumpiness and/or inhomogeneities of the ejecta, while electron scattering is the most likely cause in V2313 Oph. The wavelength-dependence of polarization in the case of V4362 Sgr suggests scattering by small dust grains, while polarization in resonance lines is the most probable cause of the observed polarization in BY Cir.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4034
- Title:
- Broadband polarisation of radio AGN
- Short Name:
- J/MNRAS/469/4034
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a broadband (1 to 3GHz), spectro-polarimetry study of the integrated emission from 100 extragalactic radio sources with the ATCA, selected to be highly linearly polarized at 1.4 GHz. We use a general purpose, polarization model-fitting procedure that describes the Faraday rotation measure (RM) and intrinsic polarization structure of up to three distinct polarized emission regions or 'RM components' of a source. Overall, 37%/52%/11% of sources are best fit by one/two/three RM components. However, these fractions are dependent on the signal-to-noise ratio (S/N) in polarization (more RM components more likely at higher S/N). In general, our analysis shows that sources with high integrated degrees of polarization at 1.4GHz have low Faraday depolarization, are typically dominated by a single RM component, have a steep spectral index, and a high intrinsic degree of polarization. After classifying our sample into radiative-mode and jet-mode AGN, we find no significant difference between the Faraday rotation or Faraday depolarization properties of jet-mode and radiative-mode AGN. However, there is a statistically significant difference in the intrinsic degree of polarization between the two types, with the jet-mode sources having more intrinsically ordered magnetic field structures than the radiative-mode sources. We also find a preferred perpendicular orientation of the intrinsic magnetic field structure of jet-mode AGN with respect to the jet direction, while no clear preference is found for the radiative-mode sources.
- ID:
- ivo://CDS.VizieR/J/A+A/435/373
- Title:
- Broadening of Fe II lines by H collisions
- Short Name:
- J/A+A/435/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data for the broadening of 24188 Fe II lines by collisions with neutral hydrogen atoms have been computed using the theory of Anstee & O'Mara (1991MNRAS.253..549A, 1995MNRAS.276..859A) as extended to singly ionised species and higher orbital angular momentum states by Barklem & O'Mara (1998MNRAS.300..863B). Data have been computed for all Fe II lines between observed energy levels in the line lists of Kurucz with loggf>-5 for which the theory is applicable. The variable energy debt parameter Ep used in computing the second order perturbation theory potential is chosen to be consistent with the long range dispersion interaction constant C_6_ computed using the f-values from Kurucz.
- ID:
- ivo://CDS.VizieR/J/A+AS/142/467
- Title:
- Broadening of metallic lines by H collisions
- Short Name:
- J/A+AS/142/467
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1 is a list of theoretical data for the broadening of metallic lines by collisions with neutral hydrogen atoms. The list contains data for 4891 spectral lines between 2300 and 13000 Angstroms of elements from Li to Ni.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/33
- Title:
- Broad H{beta} emission line in 102 Seyfert galaxies
- Short Name:
- J/ApJ/821/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 102 local (0.02=<z=<0.1) Seyfert galaxies with black hole masses M_BH_>10^7^M_{sun}_ was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M_BH_ and host galaxy properties. We study profile changes of the broad H{beta} emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad H{beta} emission line is of particular interest, not only because it is used to estimate M_BH_, but also because its strength and width are used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (~66%) of the objects, resulting in a Seyfert-type change for ~38% of the objects, likely driven by variable accretion and/or obscuration. The broad H{beta} line virtually disappears in 3/102 (~3%) extreme cases. We discuss potential causes for these changing look active galactic nuclei. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case basis or in larger samples focusing on quasars at higher redshifts, our study provides statistical information on the frequency of H{beta} line variability in a sample of low-redshift Seyfert galaxies.
2077. Broad HI absorbers
- ID:
- ivo://CDS.VizieR/J/ApJ/710/613
- Title:
- Broad HI absorbers
- Short Name:
- J/ApJ/710/613
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compile a catalog of reliable BLA (thermally broadened Ly{alpha} absorber) candidates along seven active galactic nucleus sight lines from a larger set of Ly{alpha} absorbers observed by the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST). We compare our measurements based on independent reduction and analysis of the data to those published by other research groups. We examine the detailed structure of each absorber and determine a reliable line width and column density. Purported BLAs are grouped into probable (15), possible (48), and non-BLA (56) categories. Based on 164 measured curve of growth (COG) HI line measurements, we statistically correct the observed line widths via a Monte Carlo simulation. Finally, we present new, high signal-to-noise ratio observations of several of the BLA candidate lines from Early Release Observations made by the Cosmic Origins Spectrograph on HST.
- ID:
- ivo://CDS.VizieR/J/ApJ/708/137
- Title:
- Broad-line AGNs in zCOSMOS survey
- Short Name:
- J/ApJ/708/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1<z<2.2. The unprecedented multi-wavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their spectral energy distributions (SEDs). We derive an estimate of black hole masses through the analysis of the broad MgII emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project.
- ID:
- ivo://CDS.VizieR/J/ApJ/763/133
- Title:
- Broad-line AGN with host galaxy colors
- Short Name:
- J/ApJ/763/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first quantified, statistical map of broad-line active galactic nucleus (AGN) frequency with host galaxy color and stellar mass in nearby (0.01<z<0.11) galaxies. Aperture photometry and z-band concentration measurements from the Sloan Digital Sky Survey are used to disentangle AGN and galaxy emission, resulting in estimates of uncontaminated galaxy rest-frame color, luminosity, and stellar mass. Broad-line AGNs are distributed throughout the blue cloud and green valley at a given stellar mass, and are much rarer in quiescent (red sequence) galaxies. This is in contrast to the published host galaxy properties of weaker narrow-line AGNs, indicating that broad-line AGNs occur during a different phase in galaxy evolution. More luminous broad-line AGNs have bluer host galaxies, even at fixed mass, suggesting that the same processes that fuel nuclear activity also efficiently form stars. The data favor processes that simultaneously fuel both star formation activity and rapid supermassive black hole accretion. If AGNs cause feedback on their host galaxies in the nearby universe, the evidence of galaxy-wide quenching must be delayed until after the broad-line AGN phase.
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/581
- Title:
- Broad-line Balmer decrements in blue AGN
- Short Name:
- J/MNRAS/383/581
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the broad-line Balmer decrements (H{alpha/H{beta}) for a large, homogeneous sample of Seyfert 1 galaxies and quasi-stellar objects (QSOs) using spectroscopic data obtained in the Sloan Digital Sky Survey. The sample, drawn from the Fourth Data Release, comprises 446 low-redshift (z<=0.35) active galactic nuclei (AGN) that have blue optical continua as indicated by the spectral slopes in order to minimize the effect of dust extinction. We find that (i) the distribution of the intrinsic broad-line H{alpha}/H{beta} ratio can be well described by log-Gaussian, with a peak at H{alpha}/H{beta}=3.06 and a standard deviation of about 0.03dex only; (ii) the Balmer decrement does not correlate with AGN properties such as luminosity, accretion rate and continuum slope, etc.; (iii) on average, the Balmer decrements are found to be only slightly larger in radio-loud sources (3.37) and sources having double-peaked emission-line profiles (3.27) compared to the rest of the sample. We therefore suggest that the broad-line H{alpha}/H{beta} ratio can be used as a good indicator for dust extinction in the AGN broad-line region; this is especially true for radio-quiet AGN with regular emission-line profiles, which constitute the vast majority of the AGN population.
