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1451. Local production rates of 67P/CG from MIRO
ID:
ivo://CDS.VizieR/J/A+A/603/A87
Title:
Local production rates of 67P/CG from MIRO
Short Name:
J/A+A/603/A87
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using spectroscopic and continuum data measured by the MIRO instrument on board Rosetta of comet 67P/Churyumov-Gerasimenko, it is possible to derive and track the change in the water production rate, to learn how the outgassing evolves with heliocentric distance. The MIRO data are well suited to investigate the evolution of 67P, in unprecedented spatial and temporal detail. To obtain estimates of the local effective Haser production rates we developed an efficient and reliable retrieval approach with precalculated lookup tables. We employed line area ratios (H_2_^16^O/H_2_^18^O) from pure nadir observations as the key variable, along with the Doppler shift velocity, and continuum temperature. This method was applied to the MIRO data from August 2014 until April 2016. Perihelion occurred on August 13, 2015 when the comet was 1.24AU from the Sun. During the perihelion approach, the water production rates increased by an order of magnitude, and from the observations, the derived maximum for a single observation on August 29, 2015 is (1.42+/-0.51)x10^28^. Modelling the data indicates that there is an offset in the peak outgassing, occurring 34+/-10 days after perihelion. During the pre-perihelion phase, the production rate changes with heliocentric distance as r_h_^-3.8+/-0.2^; during post- perihelion, the dependence is r_h_^-4.3+/-0.2^. The comet is calculated to have lost 0.12+/-0.06% of its mass during the perihelion passage, considering only water ice sublimation. Additionally, this method provides well- sampled data to determine the spatial distribution of outgassing versus heliocentric distance. The time evolution is definitely not uniform across the surface. Pre- and post-perihelion, the surface temperature on the southern hemisphere changes rapidly, as does the sublimation rate with an exponent of ~-6. There is a strong latitudinal dependence on the r_h_ exponent with significant variation between northern and southern hemispheres, and so the average over the comet surface may only be of limited importance. We present more detailed regional variation in the outgassing, thereby demonstrating that the highest derived production rates originate from the Wosret, Neith, and Bes regions during perihelion.
1452. Long slit spectroscopy of HII regions
ID:
ivo://CDS.VizieR/J/A+A/416/475
Title:
Long slit spectroscopy of HII regions
Short Name:
J/A+A/416/475
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the kinematical data obtained for a sample of active (Seyfert) and non active isolated spiral galaxies, based on long slit spectra along several position angles in the H{alpha} line region and, in some cases, in the Ca triplet region as well. Gas velocity distributions are presented, together with a simple circular rotation model that allows us to determine the kinematical major axes. Stellar velocity distributions are also shown.
1453. Long-slit spectroscopy of UCM galaxies
ID:
ivo://CDS.VizieR/J/A+AS/120/323
Title:
Long-slit spectroscopy of UCM galaxies
Short Name:
J/A+AS/120/323
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spectroscopic observations for the full sample of H{alpha} emission-line galaxy candidates (ELGs) from the Universidad Complutense de Madrid objective-prism survey Lists 1 and 2 have been obtained in order to investigate fully the properties of the survey constituents as well as the selection characteristics and completeness limits of the survey itself. The spectroscopic data include redshifts, line fluxes, equivalent widths, emission-line ratios, optical reddening estimates and synthesized color indexes. We find that 74% of the objects in this sample do exhibit emission lines. We compare our observational data with parameters given in the published survey lists in order to assess the usefulness of the latter. The different emission-line galaxies have been classified according to their spectra in several groups. Gray-scale images of the CCD spectra near the main emission lines, spatial profiles at the continuum and the line for [OIII]{lambda}5007 and H{alpha} lines, as well as plots of the coadded spectra of selected galaxies are presented, and a number of peculiar objects are described.
1454. Long-term monitoring of NGC 5548
ID:
ivo://CDS.VizieR/J/ApJ/779/109
Title:
Long-term monitoring of NGC 5548
Short Name:
J/ApJ/779/109
Date:
21 Oct 2021
Publisher:
CDS
Description:
The narrow [OIII]{lambda}{lambda}4959,5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3pc and is denser (n_e_~10^5^/cm3) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad H{beta} emission-line light curves for the period 1988-2008.
1455. Long-term optical monitoring of E1821+643
ID:
ivo://CDS.VizieR/J/ApJS/222/25
Title:
Long-term optical monitoring of E1821+643
Short Name:
J/ApJS/222/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of the first long-term (1990-2014) optical spectrophotometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift, high-luminosity, radio-quiet quasar. In the monitored period, the continua and H{gamma} fluxes changed about two times, while the H{beta} flux changed about 1.4 times. We found periodical variations in the photometric flux with periods of 1200, 1850, and 4000 days, and 4500-day periodicity in the spectroscopic variations. However, the periodicity of 4000-4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, but with small significance level, while the 1850-day period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000km/s. However, H{beta} shows a broader mean profile and has a larger time lag ({tau}~120 days) than H{gamma} ({tau}~60 days). We estimate that the mass of the black hole is ~2.6x10^9^M_{sun}_. The obtained results are discussed in the frame of the binary black hole hypothesis. To explain the periodicity in the flux variability and high redshift of the broad lines, we discuss a scenario where dense, gas-rich, cloudy-like structures are orbiting around a recoiling black hole.
1456. Long-term periodic variability in gamma Cas
ID:
ivo://CDS.VizieR/J/A+A/284/515
Title:
Long-term periodic variability in gamma Cas
Short Name:
J/A+A/284/515
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
1457. Long-term spectral variability of NGC 4151
ID:
ivo://CDS.VizieR/J/A+A/486/99
Title:
Long-term spectral variability of NGC 4151
Short Name:
J/A+A/486/99
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of a long-term spectral monitoring of the active galactic nucleus of NGC 4151 are presented (11 years, from 1996 to 2006). High quality spectra (S/N>50 in the continuum near H{alpha} and H{beta}) were obtained in the spectral range ~4000 to 7500{AA}, with a resolution between 5 and 15 {AA}, using the 6-m and the 1-m SAO's telescopes (Russia), the GHAO's 2.1-m telescope (Cananea, Mexico), and the OAN-SPM's 2.1-m telescope (San-Pedro, Mexico). The observed fluxes of the H{alpha}, H{beta}, H{gamma} and HeII{lambda}4686 emission lines and of the continuum at the observed wavelength 5117{AA}, were corrected for the position angle, the seeing and the aperture effects. We found that the continuum and line fluxes varied strongly (up to a factor 6) during the monitoring period. The emission was maximum in 1996-1998, and there were two minima, in 2001 and in 2005. As a consequence, the spectral type of the nucleus changed from a Sy1.5 in the maximum activity state to a Sy1.8 in the minimum state. The H{alpha}, H{gamma} and He{lambda}4686 fluxes were well correlated with the H{beta} flux. The line profiles were strongly variable, showing changes of the blue and red asymmetry. The flux ratios of the blue/red wings and of the blue (or red) wing/core of H{alpha} and H{beta} varied differently. We considered three characteristic periods during which the H{beta} and H{alpha} profiles were similar: 1996-1999, 2000-2001 and 2002-2006. The line to continuum flux ratios were different; in particular during the first period (1996-2001), the lines were not correlated with the continuum and saturated at high fluxes. In the second and third period (2002-2006), where the continuum flux was small, the H{alpha} and H{beta} fluxes were well correlated to the continuum flux, meaning that the ionizing continuum was a good extrapolation of the optical continuum. The CCFs are often asymmetrical and the time lags between the lines and the continuum are badly defined indicating the presence of a complex BLR, with dimensions from a 1 to 50 light-days. We discuss the different responses of H{beta} and H{alpha} to the continuum during the monitoring period.
1458. Long-term spectroscopy of eta Carinae
ID:
ivo://CDS.VizieR/J/A+AS/133/299
Title:
Long-term spectroscopy of eta Carinae
Short Name:
J/A+AS/133/299
Date:
21 Oct 2021
Publisher:
CDS
Description:
This Table contains parameters of 655 spectral features in the spectrum of eta Carinae, in the wavelength region 3850-11000 Angstrom. The narrow and broad line components were measured separately, for the spectrum in high excitation state (year 1995) and during the "spectroscopic event" of June/1992. The spectra were collected at ESO (Chile) and LNA (Brazil) at high resolution. Several spectral lines of Fe II, [Fe II], [Fe III], [N II] ands Ca II are identifyed for the first time in the spectrum of this star. Line variability between high and low excitation states is characterized in an objective way (parameter var in the last column).
1459. Long-term variability in the radio-quiet AGN Ark120
ID:
ivo://CDS.VizieR/J/ApJS/241/33
Title:
Long-term variability in the radio-quiet AGN Ark120
Short Name:
J/ApJS/241/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the long-term variability in the optical monitoring database of Ark 120, a nearby radio-quiet active galactic nucleus (AGN) at a distance of 143Mpc (z=0.03271). We compiled the historical archival photometric and spectroscopic data since 1974 and conducted a new two-year monitoring campaign in 2015-2017, resulting in a total temporal baseline over four decades. The long-term variations in the optical continuum exhibit a wave-like pattern and the H{beta} integrated flux series varies with a similar behavior. The broad H{beta} profiles have asymmetric double peaks, which change strongly with time and tend to merge into a single peak during some epochs. The period in the optical continuum determined from various period-search methods is about 20yr, and the estimated false alarm probability with null hypothesis simulations is about 1x10^-3^. The overall variations of the broad H{beta} profiles also follow the same period. However, the present database only covers two cycles of the suggested period, which strongly encourages continued monitoring to track more cycles and confirm the periodicity. Nevertheless, in light of the possible periodicity and the complicated H{beta} profile, Ark 120 is one candidate of the nearest radio-quiet AGNs with possible periodic variability, and it is thereby a potential candidate host for a sub-parsec supermassive black hole binary.
1460. Long-term variations of kappa Dra
ID:
ivo://CDS.VizieR/J/A+A/419/607
Title:
Long-term variations of kappa Dra
Short Name:
J/A+A/419/607
Date:
21 Oct 2021
Publisher:
CDS
Description:
A summary of results of spectroscopic monitoring of the bright Be star kappa Dra carried out at the Ondrejov Observatory between 1990 and 2004 is presented. To investigate long-term variations of Kappa Dra, we focused on H{alpha}, H{beta}, H{gamma}, H{delta}, SiII 6347{AA}, SiII 6371{AA}, HeI 6678{AA}, and FeII 6456{AA} lines. We measured equivalent widths {W}, peak intensities of the double emission lines, and the central intensity of the absorption reversals relative to the adjacent continuum (I_V_, I_R_, and I_c_, respectively), and also the peak separation between violet and red peaks (Delta_nu_p). Note that {W} is taken with a negative sign for the emission line profile. Only {W}, and I_c_ were measured, of course, for the absorption lines of {HeI} and {SiII}. All measurements are collected together with heliocentric Julian dates of mid-exposures (HJDs) in Tables 2, 3 and 4.

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