Rm FWHM Research Articles

Shock–multicloud interactions in galactic outflows – II. Radiative fractal clouds and cold gas thermodynamics

ABSTRACT Galactic winds are crucial to the cosmic cycle of matter, transporting material out of the dense regions of galaxies. Observations show the coexistence of different temperature phases in such winds, which is not easy to explain. We present a set of 3D shock–multicloud simulations that account for radiative heating and cooling at temperatures between $10^2$ and $10^7\, \rm K$. The interplay between shock heating, dynamical instabilities, turbulence, and radiative heating and cooling creates a complex multiphase flow with a rain-like morphology. Cloud gas fragments and is continuously eroded, becoming efficiently mixed and mass loaded. The resulting warm mixed gas then cools down and precipitates into new dense cloudlets, which repeat the process. Thus, radiative cooling is able to sustain fast-moving dense gas by aiding condensation of gas from warm clouds and the hot wind. In the ensuing outflow, hot gas with temperatures ${\gtrsim}10^6\, \rm K$ outruns the warm and cold phases, which reach thermal equilibrium near ${\approx}10^4$ and ${\approx}10^2\, \rm K$, respectively. Although the volume filling factor of hot gas is higher in the outflow, most of the mass is concentrated in dense gas cloudlets and filaments with these temperatures. More porous multicloud layers result in more vertically extended outflows, and dense gas is more efficiently produced in more compact layers. The cold phase is not accelerated by ram pressure, but, instead, precipitates from warm and mixed gas out of thermal equilibrium. This cycle can explain the presence of high-velocity H i gas with $N_{\rm H\, \small {I}}=10^{19\!-\!21}\, \rm cm^{-2}$ and $\Delta v_{{\rm FWHM}}\lesssim 37\, \rm km\, s^{-1}$ in the Galactic Centre outflow.

Early science with the Large Millimeter Telescope: a 1.1 mm AzTEC survey of red-Herschel dusty star-forming galaxies

ABSTRACT We present Large Millimeter Telescope (LMT)/AzTEC 1.1 mm observations of ∼100 luminous high-redshift dusty star-forming galaxy candidates from the $\sim 600\,$ sq.deg Herschel-ATLAS survey, selected on the basis of their SPIRE red far-infrared colours and with $S_{500\, \mu \rm m}=35-80$ mJy. With an effective $\theta _{\rm FWHM}\approx 9.5\,$arcsec angular resolution, our observations reveal that at least 9 per cent of the targets break into multiple systems with signal-to-noise ratio ≥4 members. The fraction of multiple systems increases to ∼23 per cent (or more) if some non-detected targets are considered multiples, as suggested by the data. Combining the new AzTEC and deblended Herschel photometry, we derive photometric redshifts, infrared luminosities, and star formation rates. While the median redshifts of the multiple and single systems are similar (zmed ≈ 3.6), the redshift distribution of the latter is skewed towards higher redshifts. Of the AzTEC sources, ∼85 per cent lie at zphot > 3 while ∼33 per cent are at zphot > 4. This corresponds to a lower limit on the space density of ultrared sources at 4 < z < 6 of $\sim 3\times 10^{-7}\, \textrm {Mpc}^{-3}$ with a contribution to the obscured star formation of $\gtrsim 8\times 10^{-4}\, \textrm {M}_\odot \, \textrm {yr}^{-1} \, \textrm {Mpc}^{-3}$. Some of the multiple systems have members with photometric redshifts consistent among them suggesting possible physical associations. Given their angular separations, these systems are most likely galaxy over-densities and/or early-stage pre-coalescence mergers. Finally, we present 3 mm LMT/RSR spectroscopic redshifts of six red-Herschel galaxies at zspec = 3.85−6.03, two of them (at z ∼ 4.7) representing new redshift confirmations. Here, we release the AzTEC and deblended Herschel photometry as well as catalogues of the most promising interacting systems and z > 4 galaxies.

An extended size–luminosity relation for the reverberation-mapped AGNs: the role of the accretion rate

ABSTRACT For a compiled sample of 120 reverberation-mapped AGNs, the bivariate correlations of the broad-line region (BLR) size (RBLR) with the continuum luminosity at 5100 Å (L5100) and the dimensionless accretion rates ($\dot{\mathscr {M}}$) are investigated. Using our recently calibrated virial factor f, and the velocity tracer from the H β full width at half-maximum (FWHM(H β)) or the line dispersion (σH β) measured in the mean spectra, three kinds of supermassive black hole (SMBH) masses and $\dot{\mathscr {M}}$ are calculated. An extended RBLR(H β)–L5100 relation including $\dot{\mathscr {M}}$ is found to be stronger than the canonical RBLR(H β)–L5100 relation, showing smaller scatters. The observational parameters, RFe (the ratio of optical Fe ii to H β line flux) and the line profile parameter DH β ($D_{\rm H\,\beta } =\rm FWHM(H\,\beta)/\sigma _{\rm H\,\beta }$), have relations with three kinds of $\dot{\mathscr {M}}$. Using RFe and DH β to substitute $\dot{\mathscr {M}}$, extended empirical RBLR(Hβ)–L5100 relations are presented. RFe is a better ‘fix’ for the RBLR(H β)–L5100 offset than the H β shape DH β. The extended empirical RBLR(H β)–L5100 relation including RFe can be used to calculate RBLR, and thus the single-epoch SMBH mass MBH. Our measured accretion rate dependence is not consistent with the simple model of the accretion disc instability leading the BLR formation. The BLR may instead form from the inner edge of the torus, or from some other means in which BLR size is positively correlated with accretion rate and the SMBH mass.

Analysis of volume-phase-grating characteristics that a variety of refractive index distributions influence. Part 2: Analysis of spectral bandwidths and angular bandwidths, and the derivation of these equations.

To expand the spectral bandwidths with high diffraction efficiency of volume phase (VP) gratings, it is important to know the influence of a variety of refractive index distributions (RIDs) inside the recording material on the bandwidths. The influence of various graded types of RIDs on the full width at half the maximum of the spectral bandwidth (${\lambda _{\rm FWHM}}$λFWHM) and the angular bandwidth (${\theta _{\rm FWHM}}$θFWHM) is investigated in the Bragg regime. It becomes clear that various graded types of RIDs influence their bandwidths and the characteristics, and the combination of the RIDs and refractive index modulation (${{ n}_m}$nm) is the most important factor for obtaining the large bandwidths of VP gratings. Theoretically, the ${\lambda _{\rm FWHM}}$λFWHM are obtained as the values of 149.7 nm and 257.6 nm (${{ n}_m} = {0.045}$nm=0.045) for the wavelengths of 900 nm and 1550 nm, respectively. Furthermore, I have succeeded in developing the expression for ${\lambda _{\rm FWHM}}$λFWHM and ${\theta _{\rm FWHM}}$θFWHM, using the proportional characteristics of VP gratings investigated in this work. The correlative coupling-length coefficients "G-factors" devised as a variety of RID functions in the previous paper are introduced into them. It is apparent that the derived equations of the bandwidths can be adapted to any graded type of RID that changes continuously from a triangular type to a rectangular type of VP grating, which has not been reported yet. The equations have made it easy to design ${\lambda _{\rm FWHM}}$λFWHM and ${\theta _{\rm FWHM}}$θFWHM of VP gratings.

The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data

We analyse high spatial resolution near infra-red (NIR) imaging of NGC6384, a Milky Way like galaxy, using ARGOS commissioning data at the Large Binocular Telescope (LBT). ARGOS provides a stable PSF$_{\rm FWHM}\!=\!0.2"\!-\!0.3"$ AO correction of the ground layer across the LUCI2 NIR camera $4'\!\times4'$ field by using six laser guide stars (three per telescope) and a natural guide star for tip-tilt sensing and guiding. Enabled by this high spatial resolution we analyse the structure of the nuclear star cluster (NSC) and the central kiloparsec of NGC6384. We find via 2D modelling that the NSC ($r_{\rm eff}\!\simeq\!10$pc) is surrounded by a small ($r_{\rm eff}\!\simeq\!100$pc) and a larger Sersi\'c ($r_{\rm eff}\!\simeq\!400$pc), all embedded within the NGC\,6384 large-scale boxy/X-shaped bulge and disk. This proof-of-concept study shows that with the high spatial resolution achieved by ground-layer AO we can push such analysis to distances previously only accessible from space. SED-fitting to the NIR and optical HST photometry allowed to leverage the age-metallicity-extinction degeneracies and derive the effective NSC properties of an young to old population mass ratio of $8\%$ with ${\cal M}_{\rm\star,old}\!\simeq\!3.5\times10^7M_\odot$, Age$_{\rm old,\ young}\!=\!10.9\pm1.3$Gyr and 226\,Myr $\pm62\%$, metallicity [M/H]$=\!-0.11\pm0.16$ and $0.33\pm39\%$dex, and $E(B\!-\!V)\!=\!0.63$ and 1.44mag.

PKS B1740$\mathbf {-}$517: An ALMA view of the cold gas feeding a distant interacting young radio galaxy

Cold neutral gas is a key ingredient for growing the stellar and central black hole mass in galaxies throughout cosmic history. We have used the Atacama Large Millimetre Array (ALMA) to detect a rare example of redshifted $^{12}$CO(2-1) absorption in PKS B1740-517, a young ($t \sim 1.6 \times 10^{3}$ yr) and luminous ($L_{\rm 5 GHz} \sim 6.6 \times 10^{43}$ erg s$^{-1}$ ) radio galaxy at $z = 0.44$ that is undergoing a tidal interaction with at least one lower-mass companion. The coincident HI 21-cm and molecular absorption have very similar line profiles and reveal a reservoir of cold gas ($M_{\rm gas} \sim 10^{7} - 10^{8}$ M$_{\odot}$), likely distributed in a disc or ring within a few kiloparsecs of the nucleus. A separate HI component is kinematically distinct and has a very narrow line width ($\Delta{v}_{\rm FWHM} \lesssim 5$ km s$^{-1}$), consistent with a single diffuse cloud of cold ($T_{\rm k} \sim 100$ K) atomic gas. The $^{12}$CO(2-1) absorption is not associated with this component, which suggests that the cloud is either much smaller than 100 pc along our sight-line and/or located in low-metallicity gas that was possibly tidally stripped from the companion. We argue that the gas reservoir in PKS B1740-517 may have accreted onto the host galaxy $\sim$50 Myr before the young radio AGN was triggered, but has only recently reached the nucleus. This is consistent with the paradigm that powerful luminous radio galaxies are triggered by minor mergers and interactions with low-mass satellites and represent a brief, possibly recurrent, active phase in the life cycle of massive early type galaxies.

Quasars as standard candles

A tight non-linear relation exists between the X-ray and UV emission in quasars (i.e. $L_{\rm X}\propto L_{\rm UV}^{\gamma}$), with a dispersion of $\sim$0.2~dex over $\sim$3~orders of magnitude in luminosity. Here we propose a modified version of this relation which involves the broad emission lines' full-width at half maximum, $L_{\rm X}\propto L_{\rm UV}^{\hat\gamma}\upsilon_{\rm fwhm}^{\hat\beta}$. We interpret this new relation through a simple, {\it ad-hoc} model of accretion disc corona, derived from previous works where it is assumed that reconnection and magnetic loops above the accretion disc can account for the production of the primary X-ray radiation. We find that the monochromatic optical-UV (2500 \AA) and X-ray (2 keV) luminosities depend on the black hole mass and accretion rate as $L_{\rm UV}\propto M_{\rm BH}^{4/3} (\dot{M}/\dot{M}_{\rm Edd})^{2/3}$ and $L_{\rm X}\propto M_{\rm BH}^{19/21} (\dot{M}/\dot{M}_{\rm Edd})^{5/21}$, respectively. Assuming a broad line region size function of the disc luminosity $R_{\rm blr}\propto L_{\rm disc}^{0.5}$ we finally have that $L_{\rm X}\propto L_{\rm UV}^{4/7} \upsilon_{\rm fwhm}^{4/7}$. Such relation is remarkably consistent with the slopes and the normalization obtained from a fit of a sample of 545 optically selected quasars from SDSS DR7 cross matched with the latest XMM-Newton catalogue 3XMM-DR6. The homogeneous sample used here has a dispersion of 0.21 dex, which is much lower than previous works in the literature and suggests a tight physical relation between the accretion disc and the X-ray emitting corona. The proposed new relation does not evolve with time, and thus it can be employed as a cosmological indicator to robustly estimate cosmological parameters.

Lyα emitters with very large Lyα equivalent widths, EW0(Lyα) ≃ 200–400 Å, atz∼ 2

We present physical properties of spectroscopically confirmed Ly$\alpha$ emitters (LAEs) with very large rest-frame Ly$\alpha$ equivalent widths EW$_{\rm 0}$(Ly$\alpha$). Although the definition of large EW$_{\rm 0}$(Ly$\alpha$) LAEs is usually difficult due to limited statistical and systematic uncertainties, we identify six LAEs selected from $\sim 3000$ LAEs at $z\sim 2$ with reliable measurements of EW$_{\rm 0}$ (Ly$\alpha$) $\simeq 200-400$ \AA\ given by careful continuum determinations with our deep photometric and spectroscopic data. These large EW$_{\rm 0}$(Ly$\alpha$) LAEs do not have signatures of AGN, but notably small stellar masses of $M_{\rm *} = 10^{7-8}$ $M_{\rm \odot}$ and high specific star-formation rates (star formation rate per unit galaxy stellar mass) of $\sim 100$ Gyr$^{-1}$. These LAEs are characterized by the median values of $L({\rm Ly\alpha})=3.7\times 10^{42}$ erg s$^{-1}$ and $M_{\rm UV}=-18.0$ as well as the blue UV continuum slope of $\beta = -2.5\pm0.2$ and the low dust extinction $E(B-V)_{\rm *} = 0.02^{+0.04}_{-0.02}$, which indicate a high median Ly$\alpha$ escape fraction of $f_{\rm esc}^{\rm Ly\alpha}=0.68\pm0.30$. This large $f_{\rm esc}^{\rm Ly\alpha}$ value is explained by the low {\sc Hi} column density in the ISM that is consistent with FWHM of the Ly$\alpha$ line, ${\rm FWHM (Ly\alpha)}=212\pm32$ km s$^{-1}$, significantly narrower than those of small EW$_{\rm 0}$(Ly$\alpha$) LAEs. Based on the stellar evolution models, our observational constraints of the large EW$_{\rm 0}$ (Ly$\alpha$), the small $\beta$, and the rest-frame He{\sc ii} equivalent width imply that at least a half of our large EW$_{\rm 0}$(Ly$\alpha$) LAEs would have young stellar ages of $\lesssim 20$ Myr and very low metallicities of $Z<0.02 Z_\odot$ regardless of the star-formation history.

Active galactic nuclei atz∼ 1.5 – II. Black hole mass estimation by means of broad emission lines

This is the second in a series of papers aiming to test how the mass ($M_{\rm BH}$), accretion rate ($\dot{M}$) and spin ($a_{*}$) of super massive black holes (SMBHs) determine the observed properties of type-I active galactic nuclei (AGN). Our project utilizes a sample of 39 unobscured AGN at $z\simeq1.55$ observed by VLT/X-shooter, selected to map a large range in $M_{\rm BH}$ and $L/L_{\rm edd}$ and covers the most prominent UV-optical (broad) emission lines, including H$\alpha$, H$\beta$, MgII, and CIV. This paper focuses on single-epoch, "virial" $M_{\rm BH}$ determinations from broad emission lines and examines the implications of different continuum modeling approaches in line width measurements. We find that using a "local" power-law continuum instead of a physically-motivated thin disk continuum leads to only slight underestimation of the FWHM of the lines and the associated $M_{\rm BH}\left({\rm FWHM}\right)$. However, the line dispersion $\sigma_{\rm line}$ and associated $M_{\rm BH}\left(\sigma_{\rm line}\right)$ are strongly affected by the continuum placement and provides less reliable mass estimates than FWHM-based methods. Our analysis shows that H$\alpha$, H$\beta$ and MgII can be safely used for virial $M_{\rm BH}$ estimation. The CIV line, on the other hand, is not reliable in the majority of the cases, this may indicate that the gas emitting this line is not virialized. While H$\alpha$ and H$\beta$ show very similar line widths, the mean ${\rm FWHM\left(MgII\right)}$ is about 30% narrower than ${\rm FWHM\left(H\beta\right)}$. We confirm several recent suggestions to improve the accuracy in CIV-based mass estimates, relying on other UV emission lines. Such improvements do not reduce the scatter between CIV-based and Balmer-line-based mass estimates.

High-Power Distributed Feedback Lasers With Surface Gratings: Theory and Experiment

Semiconductor lasers with integrated surface gratings are known to operate with narrow spectra as well as high power and efficiency. In this paper, we present a theoretical description of DFB lasers with 80th-order waveguide gratings, fabricated by etching narrow grooves into the epitaxial layer structure. The passive gratings are simulated by mode expansion and S-matrix algorithm yielding the reflection and transmission matrices in dependence on wavelength for given parameters of the grating, such as residual layer thickness and width of the grooves. The lasing condition is solved by constructing a round-trip operator and singular-value deposition for the calculation of lasing wavelength and threshold gain. A fast simulation of DFB lasers is performed within the framework of coupled-wave theory using adapted coupling coefficients. GaAs based ridge-waveguide and narrow-stripe broad-area lasers with integrated surface gratings are experimentally shown to emit output powers of 0.6 W into a single spectral line ( $\Delta \lambda _{{\rm FWHM}} pm) and $>$ 5 W into a spectrum with width $\Delta \lambda _{95\%}\approx 0.8$ nm, respectively.

AN EMPIRICAL SEQUENCE OF DISK GAP OPENING REVEALED BY ROVIBRATIONAL CO

The fundamental rovibrational band of CO near 4.7 $\mu$m is a sensitive tracer of the presence and location of molecular gas in the planet-forming region of protoplanetary disks at 0.01--10 AU. We present a new analysis of a high-resolution spectral survey (R$\,\sim\,$96,000, or $\sim3.2\,\rm km\,s^{-1}$) of CO rovibrational lines from protoplanetary disks spanning a wide range of stellar masses and of evolutionary properties. We find that the CO emission originates in two distinct velocity components. Line widths of both components correlate strongly with disk inclination, as expected for gas in Keplerian rotation. By measuring the line flux ratios between vibrational transitions $F_{v=2-1}/F_{v=1-0}$, we find that the two velocity components are clearly distinct in excitation. The broad component ($\rm FWHM=50-200\,km\,s^{-1}$) probes the disk region near the magnetospheric accretion radius at $\approx0.05$ AU, where the gas is hot ($800-1500$ K). The narrow component ($\rm FWHM=10-50 km\,s^{-1}$) probes the disk at larger radii of 0.1--10\,AU, where the gas is typically colder (200--700 K). CO excitation temperatures and orbital radii define an empirical temperature-radius relation as a power law with index $-0.3\pm0.1$ between 0.05--3 AU. The broad CO component, co-spatial with the observed orbital distribution of hot Jupiters, is rarely detected in transitional and Herbig Ae disks, providing evidence for an early dissipation of the innermost disk. An inversion in the temperature profile beyond 3 AU is interpreted as a tracer of a regime dominated by UV pumping in largely devoid inner disks, and may be a signature of the last stage before the disk enters the gas-poor debris phase.

LabPET II, an APD-based Detector Module with PET and Counting CT Imaging Capabilities

Computed tomography (CT) is currently the standard modality to provide anatomical reference for positron emission tomography (PET) in molecular imaging applications. Since both PET and CT rely on detecting radiation to generate images, using the same detection system for data acquisition is a compelling idea even though merging PET and CT hardware imposes stringent requirements on detectors. These requirements include large signal dynamic range with high signal-to-noise ratio for good energy resolution in PET and energy-resolved photon-counting CT, high pixelization for suitable spatial resolution in CT, and high count rate capability for reasonable CT acquisition time. To meet these criteria, the avalanche photodiode (APD)-based LabPET II module is proposed as the building block for a truly combined PET/CT scanner. The module is made of two monolithic $ 4\times 8$ APD pixel arrays mounted side-by-side on a custom ceramic holder. Individual APD pixels have an active area of $ 1.1\times 1.1~\hbox{mm}^{2}$ at a 1.2 mm pitch. The APD arrays are coupled to a 12-mm high, $8 \times 8$ LYSO scintillator array made of $1.12 \times 1.12~\hbox{mm}^{2}$ pixels also at a pitch of 1.2 mm to ensure direct one-to-one coupling to individual APD pixels. The scintillator array was designed with unbound specular reflective material between pixels to maximize the difference between refractive indices and enhance total internal reflection at the crystal side surfaces for better light collection, and the APD quantum efficiency was improved to $ \sim60\%$ at 420 nm to optimize intrinsic detector performance. Mean energy resolution was $20 \pm 1\%$ at 511 keV and $ 41\pm 4\%$ at 60 keV. The measured intrinsic spatial and time resolution for PET were respectively $0.81 \pm 0.04~\hbox{mm}~{\rm FWHM}/1.57 \pm 0.04~\hbox{mm}$ FWTM and $ 3.6\pm 0.3~\hbox{ns}$ FWHM with an energy threshold of 400 keV. Initial phantom images obtained using a CT test bench demonstrated excellent contrast linearity as a function of material density. With a magnification factor of 2, a CT spatial resolution of 0.66 mm FWHM/1.2 mm FWTM, corresponding to 1.18 lp/mm at ${\rm MTF}_{10\%}/0.67~\hbox{lp/mm}$ at ${\rm MTF}_{50\%}$ , was measured, allowing 0.75 mm air holes in an Ultra-Micro Hot Spot resolution phantom to be clearly distinguished.

High Relative Cooling Power in a Multiphase Magnetocaloric FeNiB Alloy

Low-cost magnetic cooling based on the magnetocaloric effect is an energy efficient, environmentally friendly, thermal management technology. However, inadequate temperature span is often a challenge in developing a magnetic cooling system. We report the novel use of multiphase materials to enhance the working temperature span (δT <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FWHM</sub> ) of the magnetic entropy change and the relative cooling power of a Fe-Ni-B bulk alloy. The coexistence of bcc, fcc, and spinel phases results in large working temperature spans of 322.3 and 439.0 K for magnetic field change of 1 and 5 T, respectively. δT <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FWHM</sub> for this multiphase (Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">70</sub> Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">89</sub> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> alloy is about 86% higher than the corresponding value for single-phase γ-(Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">70</sub> Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">89</sub> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> alloy for ΔH = 1 T. These values are the largest for any bulk magnetocaloric material and even higher than most magnetocaloric nanoparticles. The relative cooling power is also higher than comparable materials, including the benchmark magnetocaloric material, gadolinium.

The Tully-Fisher relation for 25 000 Sloan Digital Sky Survey galaxies as a function of environment

We construct Tully-Fisher relationships (TFRs) in the $u$, $g$, $r$, $i$ and $z$ bands and stellar mass TFRs (smTFRs) for a sample of $25,698$ late spiral type galaxies (with $0.045<z<0.085$) from the Sloan Digital Sky Survey (SDSS) and study the effects of environment on the relation. We use SDSS-measured Balmer emission line widths, $v_{\rm FWHM}$, as a proxy for disc circular velocity, $v_{\rm circ}$. A priori it is not clear whether we can construct accurate TFRs given the small $3"$ diameter of the fibres used for SDSS spectroscopic measurements. However, we show by modelling the H$\alpha$ emission profile as observed through a $3"$ aperture that for galaxies at appropriate redshifts ($z>0.045$) the fibres sample enough of the disc to obtain a linear relationship between $v_{\rm FWHM}$ and $v_{\rm circ}$, allowing us to obtain a TFR and to investigate dependence on other variables. We also develop a methodology for distinguishing between astrophysical and sample bias in the fibre TFR trends. We observe the well-known steepening of the TFR in redder bands in our sample. We divide the sample of galaxies into four equal groups using projected neighbour density ($\Sigma$) quartiles and find no significant dependence on environment, extending previous work to a wider range of environments and a much larger sample. Having demonstrated that we can construct SDSS-based TFRs is very useful for future applications because of the large sample size available.

Soft X-ray contact microscopy of nematode Caenorhabditis elegans

Soft X-ray Contact Microscopy (SXCM) of Caenorhabditis elegans nematodes with typical length \(\sim 800 \mu\)m and diameter \(\sim 30 \mu\)m has been performed using the PALS laser source of wavelength \(\lambda = 1.314 \mu \)m and pulse duration \(\tau ({\rm FWHM}) = 400\) ps. Pulsed soft X-rays were generated using molybdenum and gold targets with laser intensities \(I \ge 10^{14}\) W/cm2. Images have been recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Cuticle features and several internal organs have been identified in the SXCM images including lateral field, cuticle annuli, pharynx, and hypodermal and neuronal cell nuclei.

The Cambridge–Cambridge &lt;italic&gt;ROSAT&lt;/italic&gt; Serendipity Survey – II. Classification of X-ray-luminous Galaxies

We present the results of an intermediate-resolution (1.5\AA) spectroscopic study of 17 X-ray luminous narrow emission-line galaxies previously identified in the Cambridge-Cambridge {\it ROSAT} Serendipity Survey and the {\it Einstein} Extended Medium Sensitivity Survey. Emission-line ratios reveal that the sample is composed of ten Seyfert and seven starburst galaxies. Measured linewidths for the narrow H$\alpha$ emission lines lie in the range $170-460\,$km$\,$s$^{-1}$. Five of the objects show clear evidence for asymmetry in the [OIII]$\lambda$5007 emission-line profile. Broad H$\alpha$ emission is detected in six of the Seyfert galaxies, which range in type from Seyfert 1.5 to 2. Broad H$\beta$ emission is only detected in one Seyfert galaxy. The mean full width at half maximum for the broad lines in the Seyfert galaxies is ${\rm FWHM = 3900\pm 1750\,km\,s^{-1}}$. Broad (${\rm FWHM = 2200\pm 600\,km\,s^{-1}}$) $H\alpha$ emission is also detected in three of the starburst galaxies, which could originate from stellar winds or supernovae remnants. The mean Balmer decrement for the sample is H$\alpha$/H$\beta=3$, consistent with little or no reddening for the bulk of the sample. There is no evidence for any trend with X-ray luminosity in the ratio of starburst galaxies to Seyfert galaxies. Based on our previous observations, it is therefore likely that both classes of object comprise $\sim 10\,$per cent of the $2\,$keV X-ray background.