Probing rotation in quasars using microlensing-induced line profile distortions

Microlensing-induced distortions of broad emission line profiles observed in the spectra of gravitationally lensed quasars can be used to probe the size, geometry, and kinematics of the broad-line region (BLR). To this end, single-epoch Mg II or Hα line profile distortions observed in five gravitationally lensed quasars, J1131-1231, J1226-0006, J1355-2257, J1339+1310, and HE0435-1223, have been compared with simulated ones. The simulations are based on three BLR models, a Keplerian disk (KD), an equatorial wind (EW), and a polar wind (PW), with different sizes, inclinations, and emissivities. The models that best reproduce the observed line profile distortions were identified using a Bayesian probabilistic approach. We find that the wide variety of observed line profile distortions can be reproduced with microlensing-induced distortions of line profiles generated by our BLR models. For J1131, J1226, and HE0435, the most likely model for the Mg II and Hα BLRs is either KD or EW, depending on the orientation of the magnification map with respect to the BLR axis. This shows that the line profile distortions depend on the position and orientation of the isovelocity parts of the BLR with respect to the caustic network, and not only on their different effective sizes. For the Mg II BLRs in J1355 and J1339, the EW model is preferred. For all objects, the PW model has a lower probability. As for the high-ionization C IV BLR, we conclude that disk geometries with kinematics dominated by either Keplerian rotation or equatorial outflow best reproduce the microlensing effects on the low-ionization Mg II and Hα emission line profiles. The half-light radii of the Mg II and Hα BLRs are measured in the range of 3 to 25 light-days. We also confirm that the size of the region emitting the low-ionization lines is larger than the region emitting the high-ionization lines, with a factor of four measured between the sizes of the Mg II and C IV emitting regions in J1339. Unexpectedly, the microlensing BLR radii of the Mg II and Hα BLRs are found to be systematically below the radius-luminosity (R − L) relations derived from reverberation mapping, confirming that the intrinsic dispersion of the BLR radii with respect to the R − L relations is large, but also revealing a selection bias that affects microlensing-based BLR size measurements. This bias arises from the fact that, if microlensing-induced line profile distortions are observed in a lensed quasar, the BLR radius should be comparable to the microlensing Einstein radius, which varies only weakly with typical lens and source redshifts.

Recent studies have shown that line profile distortions are commonly observed in gravitationally lensed quasar spectra. We investigate the effect of gravitational microlensing on quasar broad emission line profiles and their underlying continuum, combining the emission from simple representative BLR models with generic microlensing magnification maps. Specifically, we considered Keplerian disk, polar, and equatorial wind BLR models of various sizes. The effect of microlensing has been quantified with four observables: $\mu^{BLR}$, the total magnification of the broad emission line; $\mu^{cont}$, the magnification of the underlying continuum; as well as red/blue, RBI and wings/core, WCI, indices that characterize the line profile distortions. The simulations showed that distortions of line profiles, such as those recently observed in lensed quasars, can indeed be reproduced and attributed to the differential effect of microlensing on spatially separated regions of the BLR. While the magnification of the emission line $\mu^{BLR}$ sets an upper limit on the BLR size and, similarly, the magnification of the continuum $\mu^{cont}$ sets an upper limit on the size of the continuum source, the line profile distortions mainly depend on the BLR geometry and kinematics. We thus built (WCI,RBI) diagrams that can serve as diagnostic diagrams to discriminate between the various BLR models on the basis of quantitative measurements. It appears that a strong microlensing effect puts important constraints on the size of the BLR and on its distance to the high-magnification caustic. In that case, BLR models with different geometries and kinematics are more prone to produce distinctive line profile distortions for a limited number of caustic configurations, which facilitates their discrimination.

Microlensing of the broad emission line region (BLR) in gravitationally lensed quasars produces line profile distortions that can be used to probe the BLR size, geometry, and kinematics. Based on single-epoch spectroscopic data, we analyzed the C IV line profile distortions due to microlensing in two quasars, SDSS J133907.13+131039.6 (J1339) and SDSS J113803.73+031457.7 (J1138), complementing previous studies of microlensing in the quasars Q2237+0305 and J1004+4112. J1339 shows a strong, asymmetric line profile deformation, while J1138 shows a more modest, symmetric deformation, confirming the rich diversity of microlensing-induced spectral line deformations. To probe the C IV BLR, we compared the observed line profile deformations to simulated ones. The simulations are based on three simple BLR models, a Keplerian disk (KD), an equatorial wind (EW), and a polar wind (PW), of various sizes, inclinations, and emissivities. These models were convolved with microlensing magnification maps specific to the microlensed quasar images, which produced a large number of distorted line profiles. The models that best reproduce the observed line profile deformations were then identified using a Bayesian probabilistic approach. We find that the line profile deformations can be reproduced with the simple BLR models under consideration, with no need for more complex geometries or kinematics. The models with disk geometries (KD and EW) are preferred, while the PW model is definitely less likely. In J1339, the EW model is favored, while the KD model is preferred in Q2237+0305, suggesting that various kinematical models can dominate the C IV BLR. For J1339, we find the C IV BLR half-light radii to be r1/2 = 5.1−2.9+4.6 light-days and r1/2 = 6.7−3.8+6.0 light-days from spectra obtained in 2014 and 2017, respectively. They do agree within uncertainties. For J1138, the amplitude of microlensing is smaller and more dependent on the macro-magnification factor. From spectra obtained in 2005 (single epoch), we find r1/2 = 4.9−2.7+4.9 light-days and r1/2 = 12−8+13 light-days for two extreme values of the macro-magnification factor. Combining these new measurements with those previously obtained for the quasars Q2237+0305 and J1004+4112, we show that the BLR radii estimated from microlensing do follow the C IV radius–luminosity relation obtained from reverberation mapping, although the microlensing radii seem to be systematically smaller, which could indicate either a selection bias or a real offset.

A CCD-line module is built to upgrade conventional spectrograph to the CCD ability of advanced data acquisition as well as a cost-effective solution to the plasma diagnostic spectroscopy measurement needs. The CCD module is adapted to the ISP-51 (Lomo-Russia) spectrograph, used for light dispersion and as a wavelength pre-selector when a Fabry-Perot interferometer is positioned into the parallel optical path of the spectrograph. A high-resolution spectrometer system is developed both computerized and easy to maintain. The main advantage over conventional method of spectral line profile registration is achievement of single-shot capability. Thus the line profile distortions caused by intensity fluctuations, which occur during the scanning process are eliminated. The capability of the designed spectrometer are presented with the measurements of the resolved superfine structure of the Cd I 480 nm spectral line profile as well as analyzing Ar I 738.4 nm spectral line profile broadening resulting with the gas temperature determination of argon inductively coupled plasma at low pressure and applied power.

Theories of planet formation predict the birth of giant planets in the inner, dense, and gas-rich regions of the circumstellar disks around young stars. These are the regions from which strong CO emission is expected. Observations have so far been unable to confirm the presence of planets caught in formation. We have developed a novel method to detect a giant planet still embedded in a circumstellar disk by the distortions of the CO molecular line profiles emerging from the protoplanetary disk's surface. The method is based on the fact that a giant planet significantly perturbs the gas velocity flow in addition to distorting the disk surface density. We have calculated the emerging molecular line profiles by combining hydrodynamical models with semianalytic radiative transfer calculations. Our results have shown that a giant Jupiter-like planet can be detected using contemporary or future high-resolution near-IR spectrographs such as VLT/CRIRES or ELT/METIS. We have also studied the effects of binarity on disk perturbations. The most interesting results have been found for eccentric circumprimary disks in mid-separation binaries, for which the disk eccentricity - detectable from the asymmetric line profiles - arises from the gravitational effects of the companion star. Our detailed simulations shed new light on how to constrain the disk kinematical state as well as its eccentricity profile. Recent findings by independent groups have shown that core-accretion is severely affected by disk eccentricity, hence detection of an eccentric protoplanetary disk in a young binary system would further constrain planet formation theories.

view Abstract Citations (42) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The distortion of line profiles and velocities in the spectra of contact binaries. Hutchings, J. B. Abstract Use is made of physical models of four contact binary systems, to synthesize line profiles in their spectra. Eclipse and tidal distortion effects displace the profiles at all phases to values which overestimate the stellar velocities while blending effects, when present, tend to produce an opposing displacement. It is shown how erroneous values of mass ratios and orbital elements may be obtained. Comparison with observations bears out these results and also allows absolute values of stellar radii to be obtained. The four systems are placed on the theoretical H-R and mass-luminosity diagrams. Subject headings: line profiles mass-luminosity relation - W Ursae Majoris stars Publication: The Astrophysical Journal Pub Date: March 1973 DOI: 10.1086/151980 Bibcode: 1973ApJ...180..501H full text sources ADS | data products SIMBAD (7)

Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential magnification of spatially and kinematically separated parts of the broad line region (BLR). The quasi-simultaneous visible and near-infrared spectroscopy of the lensed quasar Q2237+0305 reveals strong microlensing-induced line deformations in the high-ionization C IVλ1549 Å and the low-ionization Hα emission lines. We use this effect to constrain the BLR size, geometry, and kinematics in Q2237+0305. For this purpose, we modeled the deformation of the emission lines for three representative BLR models: a Keplerian disk, an equatorial wind, and a biconical polar wind. We considered various inclinations with respect to the line of sight. We find that the observed microlensing effect, characterized by a set of four indices, can only be reproduced by a subsample of the considered BLR models. The microlensing analysis favors a Keplerian disk model for the regions emitting the C IV and the Hα emission lines. A polar wind model remains possible for the C IV BLR, although it is less likely. The equatorial wind model is totally excluded. A preferred inclination of the BLR of 40° is found, in agreement with expectations for a type 1 AGN and past constraints on the accretion disk inclination. The half-light radius of the BLR is r1/2 ≃ 47 ± 19 light-days, with no significant difference between the C IV and Hα BLRs. The size of the C IV BLR agrees with the radius-luminosity relation derived from reverberation mapping, while the size of the Balmer line BLR is one order of magnitude smaller, possibly revealing different quasar properties at high luminosities and high accretion rates.

We show that invaluable information on the structure quasar outflows can be obtained by considering microlensing (ML)-induced variability of absorption-line troughs in lensed quasars. Depending on the structure and geometry of the outflowing gas, such extrinsic line variability is manifested as changes to the equivalent width of the trough as well as line profile distortions. Here we consider several physically distinct outflow models having very similar spectral predictions, and show how ML-induced absorption-line variability can be used to distinguish between them. Possible merits from future systematic studies of these effects are exemplified.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLine profile distortions in laser-induced impedance change signals for wavelength determination of tunable dye lasersG. J. Beenen and E. H. PiepmeierCite this: Anal. Chem. 1981, 53, 2, 239–242Publication Date (Print):February 1, 1981Publication History Published online1 May 2002Published inissue 1 February 1981https://pubs.acs.org/doi/10.1021/ac00225a026https://doi.org/10.1021/ac00225a026research-articleACS PublicationsRequest reuse permissionsArticle Views35Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Aims. We study the 2D spectral line profile of the High Accuracy Radial Velocity Planet Searcher (HARPS), measuring its variation with position across the detector and with changing line intensity. The characterization of the line profile and its variations are important for achieving the precision of the wavelength scales of 10−10 or 3.0 cm s−1 necessary to detect Earth-twins in the habitable zone around solar-like stars. Methods. We used a laser frequency comb (LFC) with unresolved and unblended lines to probe the instrument line profile. We injected the LFC light – attenuated by various neutral density filters – into both the object and the reference fibres of HARPS, and we studied the variations of the line profiles with the line intensities. We applied moment analysis to measure the line positions, widths, and skewness as well as to characterize the line profile distortions induced by the spectrograph and detectors. Based on this, we established a model to correct for point spread function distortions by tracking the beam profiles in both fibres. Results. We demonstrate that the line profile varies with the position on the detector and as a function of line intensities. This is consistent with a charge transfer inefficiency effect on the HARPS detector. The estimate of the line position depends critically on the line profile, and therefore a change in the line amplitude effectively changes the measured position of the lines, affecting the stability of the wavelength scale of the instrument. We deduce and apply the correcting functions to re-calibrate and mitigate this effect, reducing it to a level consistent with photon noise.

The laser-cooled ions in a radio-frequency ion show a variety of peculiar line profiles as functions of laser intensity and trap potential. All these line profiles are well reproduced by a calculation based on the present theoretical model, in which the ion motion in a trap in the presence of laser radiation pressure is analyzed. The results give information about collisions of ions, and are utilized for the accurate spectroscopic measurement of the ion responses.

We present a detailed temperature and magnetic investigation of the T Tauri star V410 Tau by means of a simultaneous Doppler- and Zeeman-Doppler Imaging. Moreover we introduce a new line profile reconstruction method based on a singular value decomposition (SVD) to extract the weak polarized line profiles. One of the key features of the line profile reconstruction is that the SVD line profiles are amenable to radiative transfer modeling within our Zeeman-Doppler Imaging code iMap. The code also utilizes a new iterative regularization scheme which is independent of any additional surface constraints. To provide more stability a vital part of our inversion strategy is the inversion of both Stokes I and Stokes V profiles to simultaneously reconstruct the temperature and magnetic field surface distribution of V410 Tau. A new image-shear analysis is also implemented to allow the search for image and line profile distortions induced by a differential rotation of the star. The magnetic field structure we obtain for V410 Tau shows a good spatial correlation with the surface temperature and is dominated by a strong field within the cool polar spot. The Zeeman-Doppler maps exhibit a large-scale organization of both polarities around the polar cap in the form of a twisted bipolar structure. The magnetic field reaches a value of almost 2 kG within the polar region but smaller fields are also present down to lower latitudes. The pronounced non-axisymmetric field structure and the non-detection of a differential rotation for V410 Tau supports the idea of an underlying $\alpha^2$-type dynamo, which is predicted for weak-lined T Tauri stars.

J1004+4112 is a lensed quasar for which the first broad emission line profile deformations due to microlensing were identified. Detailed interpretations of these features have nevertheless remained controversial. Based on 15 spectra obtained from 2003 to 2018, in this work, we revisit the microlensing effect that distorts the C IV broad emission line profile in J1004+4112. We take advantage of recent measurements of the image macro-magnification ratios, along with the fact that at one epoch, image B was not microlensed, thus constituting a reference spectrum to unambiguously characterize the microlensing effect observed in image A. After disentangling the microlensing in images A and B, we show that the microlensing-induced line profile distortions in image A, although variable, are remarkably similar over a period of 15 years. We find they are characterized by a strong magnification of the blue part of the line profile, a strong demagnification of the red part of the line profile, and a small-to-negligible demagnification of the line core. We used the microlensing effect, characterized by either the full magnification profile of the C IV emission line or a set of four integrated indices, to constrain the broad emission-line region (BLR) size, geometry, and kinematics. For this purpose, we modeled the deformation of the emission lines considering three simple, representative BLR models: a Keplerian disk, an equatorial wind, and a biconical polar wind, with various inclinations with respect to the line of sight. We find that the observed magnification profile of the C IV emission line in J1004+4112 can be reproduced with the simple BLR models we considered, without the need for more complex BLR features. The magnification appears dominated by the position of the BLR with respect to the caustic network – and not by the velocity-dependent size of the BLR. The favored models for the C IV BLR are either the Keplerian disk or the equatorial wind, depending on the orientation of the BLR axis with respect to the caustic network. We also find that the polar wind model can be discarded. We measured the C IV BLR half-light radius as r1/2=2.8−1.7+2.0 light-days. This value is smaller than the BLR radius expected from the radius-luminosity relation derived from reverberation mapping, but it is still in reasonable agreement given the large uncertainties.

The possibility of an instantaneous determination of the Balmer alpha (Hα) line profile of hydrogen atoms in large plasma devices by rapid-frequency-scan (RAFS) laser spectroscopy is discussed. A detailed analysis of the SN ratio shows that, although the SN ratio in Hα line profile measurements by RAFS is smaller than those in neutral hydrogen density measurements, a remarkable improvement can be obtained by the choice of the optimum saturation parameter and the long-pulse operation. Based on the experiment of the Hα profile measurement in a hydrogen DC glow discharge plasma by RAFS, the profile distortion in saturated excitation is evaluated. The SN ratio in the profile measurement by RAFS for Heliotron E plasma is estimated from the data on the neutral density measurement.

A combination of a Fabry-Perot interferometer, a grating monochromator and an optical multichannel analyser is used to measure argon ion line profiles with a spectral resolution lambda / Delta lambda of 2*106 and a temporal resolution of 500 ns. A deconvolution technique using Voigt profiles allows one to determine the argon ion temperature in pseudospark discharges. The main advantage over conventional methods is the registration of the whole line profile in a single exposure, which eliminates line profile distortions caused by intensity fluctuations which occur during a scanning process. Using the monochromator as a filtering element allows attainment of high resolution even in wavelength regions of high spectral line density, whereas the optical multichannel analyser provides single shot capability.