Emission Line Spectrum Research Articles

Suppression of self-absorption in laser-induced breakdown spectroscopy using a double pulse orthogonal configuration to create vacuum-like conditions in atmospheric air pressure

Self-absorption, which is known to severely disturb identification of the emission peak intensity in emission-based spectroscopy, was first studied using ordinary single pulse laser-induced breakdown spectroscopy (LIBS). It was found that severe self-absorption, with an evident self-reversal, occurs in the resonance emission lines of high concentration Na, K, and Al, and thus it is impossible to obtain the linear calibration curve required for quantitative analysis. To overcome this problem, we introduce a double pulse orthogonal technique in which the first laser is fired in a parallel orientation at a varied distance of 2–6 mm from the sample surface. It is well known that the strong shock wave generated by this laser irradiation temporarily creates a vacuum-like condition immediately in front of the sample surface. This action is followed by a second laser irradiation oriented perpendicular to the sample surface. The sample ablated by the second laser irradiation expands following the shockwave excitation process in the vacuum-like air atmosphere created by the first laser. The obtained spectra of the resonance emission lines of high concentration Na, K, and Al are free from the self-reversal and weakly affected by the self-absorption effect. A linear calibration curve that intercepts near zero point for K element over a wide concentration range is also demonstrated in this study. This simple modification is considered notably helpful in overcoming the self-absorption that occurs in ordinary single pulse atmospheric pressure LIBS.

Rapid Detection Of Heavy Metals On Waste-Water Polluted Soils Using Laser Induced Breakdown Spectroscopy

The Laser Induced Breakdown Spectroscopy (LIBS) method was successfully used to detect heavy metal elements in the soil polluted by wastewater from paper mills. The study was conducted using a Nd: YAG pulse laser with a wavelength of 532 nm at 83 mJ energy and 5 torr air pressure. The laser is fired at a soil sample that has been made in the form of pellets to produce plasma. The plasma emission spectrum formed is then detected by multichannel analyzer (OMA) to obtain the emission line spectrum that represents the content of atoms and molecules in the soil sample. The spectrum detected by OMA is then compared to the standard reference spectrum at NIST (National Institute of Standards and Technology) to find out the contents of an element on a contaminated soil sample. several types of heavy metal elements Fe, Cr, Cu, Al, Cd and Mn in soils contaminated by wastewater were detected using LIBS method. Based on research results, the LIBS method is very well used for the detection of heavy metal content in polluted soils.

Chandra High Energy Transmission Gratings Spectra of V3890 Sgr

Abstract The recurrent nova (RN) V3890 Sgr was observed during the seventh day after the onset of its most recent outburst, with the Chandra ACIS-S camera and High Energy Transmission Gratings. A rich emission line spectrum was detected, due to transitions of Fe-L and K-shell ions ranging from neon to iron. The measured absorbed flux is ≈10−10 erg cm−2 s−1 in the 1.4–15 Å range (0.77–8.86 keV). The line profiles are asymmetric, blueshifted, and skewed toward the blue side, as if the ejecta moving toward us are less absorbed than the receding ejecta. The full width at half-maximum of most emission lines is 1000–1200 km s−1, with some extended blue wings. The spectrum is thermal and consistent with a plasma in collisional ionization equilibrium with column density 1.3 × 1022 cm−2 and at least two components at temperatures of about 1 and 4 keV, possibly a forward and a reverse shock, or regions with differently mixed ejecta and a red giant wind. The spectrum is remarkably similar to the symbiotic RNe V745 Sco and RS Oph, but we cannot distinguish whether the shocks occurred at a distance of a few au from the red giant, or near the giant’s photosphere, in a high-density medium containing only a low mass. The ratios of the flux in lines of aluminum, magnesium, and neon relative to the flux in lines of silicon and iron probably indicate a carbon–oxygen white dwarf.

Peculiar emission line spectra of core extremely red BOSS quasars at z∼2–3: orientation and/or evolution?

Context. Core extremely red quasars (core ERQ) have been proposed to represent an intermediate evolutionary phase in which a heavily obscured quasar blows out the circumnuclear interstellar medium with very energetic outflows before it becomes an optical quasar. Aims. We investigate whether the properties of core ERQ fit the AGN orientation-based unification scenario. Methods. We revised the general UV and optical emission line properties of core ERQ in the context of the orientation-based scenario. We used diagnostic diagrams based on UV emission line ratios and UV-to-optical line kinematic information to compare the physical and kinematic gas properties of core ERQ with those of other luminous narrow- and broad-line AGN. In particular, we provide a revised comparison of the [OIII] kinematics in 21 core ERQ (20 from Perrotta et al. 2019, MNRAS, 488, 4126 and SDSS J171420.38+414815.7, based on GTC EMIR near-infrared spectroscopy) with other samples of quasars with matching luminosity with the aim of evaluating whether core ERQ host the most extreme [OIII] outflows. Results. The UV line ratios suggest that the physical properties (e.g., density and metallicity) of the ionised gas in core ERQ are similar to those observed in the broad-line region of blue nitrogen-loud quasars. The [OIII] outflow velocities of core ERQ are on average consistent with those of very luminous blue type 1 quasars, although extreme outflows are much more frequent in core ERQ. These similarities can be explained in the context of the AGN unification model under the assumption that core ERQ are viewed with an intermediate orientation between type 2 (edge-on) and type 1 (face-on) quasars. Conclusions. We propose that core ERQ are very luminous but otherwise normal quasars viewed at an intermediate orientation. This orientation allows a direct view of the outer part of the large broad-line region from which core ERQ UV line emission originates; the extreme [OIII] outflow velocities are instead a consequence of the very high luminosity of core ERQ.

The Lyman Continuum Escape Survey. II. Ionizing Radiation as a Function of the [O iii]/[O ii] Line Ratio

Abstract We discuss the rest-frame optical emission line spectra of a large (∼50) sample of z ∼ 3.1 Lyα emitting galaxies (LAEs) whose physical properties suggest such sources are promising analogs of galaxies in the reionization era. Reliable Lyman continuum (LyC) escape fractions have now been determined for a large sample of such LAEs from the LymAn Continuum Escape Survey (LACES) undertaken via deep Hubble Space Telescope imaging in the SSA22 survey area reported in Fletcher et al. Using new measures of [O ii] emission secured from Keck MOSFIRE spectra we re-examine, for a larger sample, earlier claims that LyC leakages may correlate with the nebular emission line ratio [O iii]/[O ii] as expected for density-bound H ii regions. We find that a large [O iii]/[O ii] line ratio is indeed a necessary condition for LyC leakage, strengthening earlier claims made using smaller samples at various redshifts. However, not all LAEs with large [O iii]/[O ii] line ratios are leakers and leaking radiation appears not to be associated with differences in other spectral diagnostics. This suggests the detection of leaking radiation is modulated by an additional property, possibly the viewing angle for porous H ii regions. We discuss our new results in the context of the striking bimodality of LAE leakers and non-leakers found in the LACES program and the implications for the sources of cosmic reionization.

Stratified disc wind models for the AGN broad-line region: ultraviolet, optical, and X-ray properties

ABSTRACT The origin, geometry, and kinematics of the broad-line region (BLR) gas in quasars and active galactic nuclei (AGN) are uncertain. We demonstrate that clumpy biconical disc winds illuminated by an AGN continuum can produce BLR-like spectra. We first use a simple toy model to illustrate that disc winds make quite good BLR candidates, because they are self-shielded flows and can cover a large portion of the ionizing flux-density (ϕH-nH) plane. We then conduct Monte Carlo radiative transfer and photoionization calculations, which fully account for self-shielding and multiple scattering in a non-spherical geometry. The emergent model spectra show broad emission lines with equivalent widths and line ratios comparable to those observed in AGN, provided that the wind has a volume filling factor of fV ≲ 0.1. Similar emission line spectra are produced for a variety of wind geometries (polar or equatorial) and for launch radii that differ by an order of magnitude. The line emission arises almost exclusively from plasma travelling below the escape velocity, implying that ‘failed winds’ are important BLR candidates. The behaviour of a line-emitting wind (and possibly any ‘smooth flow’ BLR model) is similar to that of the locally optimally emitting cloud model originally proposed by Baldwin et al. (1995), except that the gradients in ionization state and temperature are large-scale and continuous, rather than within or between distinct clouds. Our models also produce UV absorption lines and X-ray absorption features, and the stratified ionization structure can partially explain the different classes of broad absorption line quasars.

Detection of heavy metal containment of soil pollution due to waste of paper industry using Nd:YAG laser induced breakdown spectroscopy

Detection of heavy metal containment of soil pollution has been made by using laser-induced breakdown spectroscopy (LIBS). A pulsed Nd:YAG laser (1064 nm, 8 ns, 200 mJ) was focused on to a soil sample, which is prepared in the form of pellet, at atmospheric pressure. Emission spectra taken from the waste-contaminated soil and uncontaminated soil were obtained. Plasma emissions are then detected using a multichannel analyzer (OMA) to obtain the emission line spectrum that represents the content of atoms and molecules in the target material. The spectrum is recorded and compared with the spectrum of reference standards of atoms, ions and molecules (National Institute of Standards and Technology/NIST) so that the atomic and molecular content in the sample can be known. From the results of the study it was found that there are elements of heavy metals in the form of Fe, Cd, and Mg in polluted soils.

Comparison of the photoionisation modelling results for planetary nebulae with the observed data

The grid of new photoionisation models for planetary nebulae (PNe) along the evolutionary tracks of their nuclei was calculated, taking into account the dust presence with abundances that correspond to the averaged ones for Milky Way and Large Magellanic Cloud. The calculations were performed by the last version of G. Ferland's code Cloudy v17.01 using the semi-empirical law derived by Golovatyy-Mal'kov to describe the radial density distribution of matter in the nebular envelope of PN. Resulting modelling spectra were compared with the corresponding observed emission line spectra of PNe in optical range, obtained previously by other authors. Also the database of observations by the Infrared Space Observatory and Spitzer have been used to compare the results of synthetic photometry with the observed photometric data. It was shown that the intensities of strong emission lines in optical range as well as the observed color-color diagrams obtained using total fluxes in the 3.6 μm, 4.5μm, 8.0μm and 24.0 μm bands are reproduced very well by our models, while the results of synthetic IR-photometry based on total fluxes in the band 5.8 μm show discrepancies with corresponding observed data.

Analysis of Time-resolved Spectra of Ejecta from Hypervelocity Impacts

Ejecta from hypervelocity impact includes not only fragments but also luminous vapor cloud with plasma. The plasma (i.e. plasma density) is an important parameter for estimating the risk of discharge on solar array paddle or power harness of spacecraft. We carried out hypervelocity impact experiments using a two-stage light gas gun to analyze luminous vapor cloud and plasma from impacts of the different projectile and target materials. We measured luminous vapor cloud and plasma by using a high-speed video camera and a streak camera spectroscopy, which gives time-resolved spectra and a plasma probe. From the time-resolved spectra, the temperature of the luminous vapor cloud was calculated by fitting the black body radiation from a continuous spectrum of the luminous vapor cloud. Also, we compared and investigated the temporal change of each emission line spectrum from impacts of different target and projectile materials.

New deep coronal spectra from the 2017 total solar eclipse

Context. The origin of the high temperature of the solar corona, in both the inner bright parts and the more outer parts showing flows toward the solar wind, is not understood well yet. Total eclipses permit a deep analysis of both the inner and the outer parts of the corona using the continuum white-light (W-L) radiations from electrons (K-corona), the superposed spectrum of forbidden emission lines from ions (E-corona), and the dust component with F-lines (F-corona). Aims. By sufficiently dispersing the W-L spectrum, the Fraunhofer (F) spectrum of the dust component of the corona appears and the continuum Thomson radiation can be evaluated. The superposed emission lines of ions with different degrees of ionization are studied to allow the measurement of temperatures, non-thermal velocities, Doppler shifts, and abundances to constrain the proposed heating mechanisms and understand the origin of flows that lead to solar wind. Methods. We describe a slit spectroscopic experiment of high spectral resolution to provide an analysis of the most typical parts of the quasi-minimum type corona observed during the total solar eclipse of Aug. 21, 2017 from Idaho, USA. Streamers, active region enhancements, and polar coronal holes (CHs) are measured well using deep spectra. Results. Sixty spectra are obtained during the totality with a long slit, covering ±3 solar radii in the range of 510 nm to 590 nm. The K+F continuum corona is exposed well up to two solar radii. The F-corona can be measured even at the solar limb. New weak emission lines were discovered or confirmed. The rarely observed Ar X line is detected almost everywhere; the Fe XIV and Ni XIII lines are clearly detected everywhere. For the first time hot lines are also measured inside the CH regions. The radial variations of the non-thermal turbulent velocities of the lines do not show a great departure from the average values. No significantly large Doppler shifts are seen anywhere in the inner or the middle corona. The wings of the Fe XIV line show some non-Gaussianity. Conclusions. Deep slit coronal spectra offered an opportunity for diagnosing several aspects of coronal physics during a well observed total eclipse without extended investments. The analysis of the ionic emission line profiles offers several powerful diagnostics of the coronal dynamics; the precise measurement of the F-continuum component provides insight into the ubiquitous dust corona at the solar limb.

The New EXor Outburst of ESO-Hα 99 Observed by Gaia ATLAS and TESS

Abstract We report photometry and spectroscopy of the outburst of the young stellar object ESO-Hα99. The outburst was first noticed in Gaia alert Gaia18dvc and later by the Asteroid Terrestrial-impact Last Alert System (ATLAS). We have established the outburst light curve with archival ATLAS orange filter photometry, Gaia data, new V-band photometry, and J, H, and K s photometry from the Infrared Imaging System (IRIS) and the United Kingdom Infrared Telescope (UKIRT). The brightness has fluctuated several times near the light curve maximum. The Transiting Exoplanet Survey Satellite (TESS) satellite observed ESO-Hα 99 with high cadence during one of these minor minima and found brightness fluctuations on timescales of days and hours. Imaging with UKIRT shows the outline of an outflow cavity, and we find one knot of emission, now named MHO 1520, on the symmetry axis of this nebula, indicating recent collimated outflow activity from ESO-Hα 99. Its pre-outburst SED shows a flat far-infrared spectrum, confirming its early evolutionary state and its similarity to other deeply embedded objects in the broader EXor class. The pre-outburst luminosity is 34 L ⊙, a much higher luminosity than typical EXors, indicating that ESO-Hα 99 may be a star of intermediate mass. Infrared and optical spectroscopy show a rich emission-line spectrum, including H i lines, strong red Ca ii emission, as well as infrared CO bandhead emission, all characteristic EXors in the broadest sense. Comparison of the present spectra with an optical spectrum obtained in 1993, presumably in the quiescent state of the object, shows that during the present outburst the continuum component of the spectrum has increased notably more than the emission lines. The Hα equivalent width during the outburst is down to one-half of its 1993 level, and shock-excited emission lines are much less prominent.

The MOSDEF Survey: A Census of AGN-driven Ionized Outflows at z = 1.4–3.8

Abstract Using data from the MOSFIRE Deep Evolution Field (MOSDEF) survey, we present a census of active galactic nucleus (AGN)–driven ionized outflows in a sample of 159 AGNs at 1.4 ≤ z ≤ 3.8. The sample spans AGN bolometric luminosities of 1044–47 erg s−1 and includes both quiescent and star-forming galaxies extending across 3 orders of magnitude in stellar mass. We identify and characterize outflows from the Hβ, [O iii], Hα, and [N ii] emission line spectra. We detect outflows in 17% of the AGNs, seven times more often than in a mass-matched sample of inactive galaxies in MOSDEF. The outflows are fast and galaxy-wide, with velocities of ∼400–3500 km s and spatial extents of 0.3–11.0 kpc. The incidence of outflows among AGNs is independent of the stellar mass of the host galaxy, with outflows detected in both star-forming and quiescent galaxies. This suggests that outflows exist across different phases in galaxy evolution. We investigate relations between outflow kinematic, spatial, and energetic properties and both AGN and host galaxy properties. Our results show that AGN-driven outflows are widespread in galaxies along the star-forming main sequence. The mass-loading factors of the outflows are typically 0.1–1 and increase with AGN luminosity, capable of exceeding unity at . In these more luminous sources, the ionized outflow alone is likely sufficient to regulate star formation and, when combined with outflowing neutral and molecular gas, may be able to quench star formation in their host galaxies.

The 50–100 pc scale parent stellar populations of Type II supernovae and limitations of single star evolution models

ABSTRACT There is observational evidence of a dearth in core-collapse supernova (ccSN) explosions from stars with zero-age main-sequence (ZAMS) mass M0 ≈ 17–30M⊙, referred to as the ‘red supergiant problem’. However, simulations now predict that above 20 M⊙ we should indeed only expect stars within certain pockets of M0 to produce a visible SN explosion. Validating these predictions requires large numbers of ccSNe of different types with measured M0, which is challenging. In this paper, we explore the reliability of using host galaxy emission lines and the H α equivalent width to constrain the age, and thus the M0 of ccSNe progenitors. We use Binary Population and Spectral Synthesis models to infer a stellar population age from MUSE observations of the ionized gas properties and H α EW at the location of eleven ccSNe with reliable M0 measurements. Comparing our results to published M0 values, we find that models that do not consider binary systems yield stellar ages that are systematically too young (thus M0 too large), whereas accounting for binary system interactions typically overpredict the stellar age (thus underpredict M0). Taking into account the effects of photon leakage bring our M0 estimates in much closer agreement with expectations. These results highlight the need for careful modelling of diffuse environments, such as are present in the vicinity of Type II SNe, before ionized emission line spectra can be used as reliable tracers of progenitor stellar age.

Constraints on the production and escape of ionizing radiation from the emission-line spectra of metal-poor star-forming galaxies

ABSTRACT We explore the production and escape of ionizing photons in young galaxies by investigating the ultraviolet and optical emission-line properties of models of ionization-bounded and density-bounded H ii regions, active-galactic-nucleus (AGN) narrow-line regions, and radiative shocks computed all using the same physically consistent description of element abundances and depletion on to dust grains down to very low metallicities. We compare these models with a reference sample of metal-poor star-forming galaxies and Lyman-continuum (LyC) leakers at various redshifts, which allows the simultaneous exploration of more spectral diagnostics than typically available at once for individual subsamples. We confirm that current single- and binary-star population synthesis models do not produce hard-enough radiation to account for the high-ionization emission of the most metal-poor galaxies. Introducing either an AGN or radiative-shock component brings models into agreement with observations. A published model including X-ray binaries is an attractive alternative to reproduce the observed rise in He iiλ4686/H β ratio with decreasing oxygen abundance in metal-poor star-forming galaxies, but not the high observed He iiλ4686/Hβ ratios of galaxies with large EW(Hβ). A source of harder ionizing radiation appears to be required in these extreme objects, such as an AGN or radiative-shock component, perhaps linked to an initial-mass-function bias towards massive stars at low metallicity. This would also account for the surprisingly high [O i]/[O iii] ratios of confirmed LyC leakers relative to ionization-bounded models. We find no simple by-eye diagnostic of the nature of ionizing sources and the escape of LyC photon, which require proper simultaneous fits of several lines to be discriminated against.

High-resolution Near-infrared Spectroscopy of HD 100546. IV. Orbiting Companion Disappears on Schedule

Abstract HD 100546 is a Herbig Ae/Be star surrounded by a disk with a large central region that is cleared of gas and dust (i.e., an inner hole). High-resolution near-infrared spectroscopy reveals a rich emission spectrum of fundamental rovibrational CO emission lines whose time variable properties point to the presence of an orbiting companion within the hole. The Doppler shift and spectroastrometric signal of the CO v = 1−0 P26 line, observed from 2003 to 2013, are consistent with a source of excess CO emission that orbits the star near the inner rim of the disk. The properties of the excess emission are consistent with those of a circumplanetary disk. In this paper, we report follow-up observations that confirm our earlier prediction that the orbiting source of excess emission would disappear behind the near side of the inner rim of the outer disk in 2017. We find that while the hot band CO lines remained unchanged in 2017, the v = 1−0 P26 line and its spectroastrometric signal returned to the profile observed in 2003. With these new observations, we further constrain the origin of the emission and discuss possible ways of confirming the presence of an orbiting planetary companion in the inner disk.

The Structure of the Orion Nebula in the Direction of θ1 Ori C

Abstract We have used existing optical emission and absorption lines, [C ii] emission lines, and H i absorption lines to create a new model for a central column of material near the Trapezium region of the Orion Nebula. This was necessary because recent high spectral resolution spectra of optical emission lines and imaging spectra in the [C ii] 158 μm line have shown that there are new velocity systems associated with the foreground Veil and the material lying between θ 1 Ori C and the main ionization front of the nebula. When a family of models generated with the spectral synthesis code Cloudy were compared with the surface brightness of the emission lines and strengths of the Veil absorption lines seen in the Trapezium stars, distances from θ 1 Ori C were derived, with the closest, highest ionization layer being 1.3 pc. The line-of-sight distance of this layer is comparable with the size of the inner Huygens region in the plane of the sky. These layers are all blueshifted with respect to the Orion Nebula Cluster of stars, probably because of the pressure of a hot central bubble created by θ 1 Ori C's stellar wind. We find velocity components that are ascribed to both sides of this bubble. Our analysis shows that the foreground [C ii] 158 μm emission is part of a previously identified layer that forms a portion of a recently discovered expanding shell of material covering most of the larger Extended Orion Nebula.

Integral field spectroscopy of Green Peas – I. Disentangling disc-like turbulence and strong outflow kinematics in SDSS J083843.63+385350.5

ABSTRACT Integral field spectroscopy is well known for providing detailed insight of extended sources thanks to the possibility of handling space resolved spectroscopic information. Simple and straightforward analysis such as single line fitting yields interesting results, although it might miss a more complete picture in many cases. Violent star-forming regions, such as starburst galaxies, display very complex emission line profiles due to multiple kinematic components superposed in the line of sight. We perform a spatially resolved kinematical study of a single Green Pea (GP) galaxy, SDSS J083843.63+385350.5, using a new method for analysing integral field unit observations of emission line spectra. The method considers the presence of multiple components in the emission line profiles and makes use of a statistical indicator to determine the meaningful number of components to fit the observed profiles. We are able to identify three distinct kinematic features throughout the field and discuss their link with a rotating component, a strong outflow, and a turbulent mixing layer. We also derive an updated star formation rate for SDSS J0838 and discuss the link between the observed signatures of a large-scale outflow and of the Lyman continuum leakage detected in GP galaxies.

Discovery and analysis of a ULX nebula in NGC 3521

ABSTRACT We present Very Large Telescope/X-shooter and Chandra X-ray observatory/ACIS observations of the ULX [SST2011] J110545.62 + 000016.2 in the galaxy NGC 3521. The source identified as a candidate near-infrared counterpart to the ULX in our previous study shows an emission line spectrum of numerous recombination and forbidden lines in the visible and near-infrared spectral regime. The emission from the candidate counterpart is spatially extended (∼34 pc) and appears to be connected with an adjacent H ii region, located ∼138 pc to the NE. The measured velocities of the emission lines confirm that both the candidate counterpart and H ii region reside in NGC 3521. The intensity ratios of the emission lines from the ULX counterpart show that the line emission originates from the combined effect of shock and photoionization of low metallicity (12 + log (O/H) = 8.19 ± 0.11) gas. Unfortunately, there is no identifiable spectral signature directly related to the photosphere of the mass-donor star in our spectrum. From the archival Chandra data, we derive the X-ray luminosity of the source in the 0.3–7 keV range to be (1.9 ± 0.8) × 1040 er g cm−2 s−1, almost a factor of four higher than what is previously reported.

GAUSSPY+: A fully automated Gaussian decomposition package for emission line spectra

Our understanding of the dynamics of the interstellar medium is informed by the study of the detailed velocity structure of emission line observations. One approach to study the velocity structure is to decompose the spectra into individual velocity components; this leads to a description of the data set that is significantly reduced in complexity. However, this decomposition requires full automation lest it become prohibitive for large data sets, such as Galactic plane surveys. We developed GAUSSPY+, a fully automated Gaussian decomposition package that can be applied to emission line data sets, especially large surveys of HI and isotopologues of CO. We built our package upon the existing GAUSSPY algorithm and significantly improved its performance for noisy data. New functionalities of GAUSSPY+ include: (i) automated preparatory steps, such as an accurate noise estimation, which can also be used as stand-alone applications; (ii) an improved fitting routine; (iii) an automated spatial refitting routine that can add spatial coherence to the decomposition results by refitting spectra based on neighbouring fit solutions. We thoroughly tested the performance of GAUSSPY+ on synthetic spectra and a test field from the Galactic Ring Survey. We found that GAUSSPY+ can deal with cases of complex emission and even low to moderate signal-to-noise values.

Spectropolarimetry of the superwind filaments of the starburst galaxy M 82 II: Kinematics of the dust surrounding the nuclear starburst

Abstract We performed deep spectropolarimetric observations of the prototypical starburst galaxy M 82 with the Subaru Telescope in order to study the kinematics of the dust outflow. We obtained optical polarized emission-line spectra up to ∼4 kpc away from the nucleus of the galaxy along three position angles, 138°, 150°, and 179° within the conical outflowing wind (superwind). The Hα emission line in the superwind is strongly polarized and the polarization pattern shows dust scattering of central light sources, being consistent with the previous works. The intensity weighted polarization degree of the Hα line reaches ∼30% at maximum. There are at least two light sources at the central region of the galaxy; one is located at the near-infrared nucleus and the other resides at one of the peaks of the 3 mm radio and molecular gas emission. The outer (>1 kpc) dust is illuminated by the former, whereas the inner dust is scattering the light from the latter. We also investigated the dust motion from the velocity field of the polarized Hα emission line. The dust is accelerated outward on the northwest side of the nucleus. A simple bi-conical dust outflow model shows that the outflow velocity of the dust reaches ≳ 300–450 km s−1 at ∼4 kpc from the nucleus, suggesting that some portion of the dust escapes from the gravitational potential of M 82 into the intergalactic space. At some regions on the southeast side, in particular along the position angle of 138°, the dust has a radial velocity that is slower than the systemic velocity of the galaxy, apparently suggesting inflowing motion toward the nucleus. These components are spatially consistent with a part of the molecular gas stream, which is kinematically independent of the outflow gas; thus the apparent inflow motion of the dust reflects the streaming motion associated with the molecular gas stream.