Gerald Cecil

The SAMI Galaxy Survey: instrument specification and target selection

The SAMI Galaxy Survey will observe 3400 galaxies with the Sydney-AAO Multi- object Integral-field spectrograph (SAMI) on the Anglo-Australian Telescope (AAT) in a 3-year survey which began in 2013. We present the throughput of the SAMI system, the science basis and specifications for the target selection, the survey observation plan and the combined properties of the selected galaxies. The survey includes four volume-limited galaxy samples based on cuts in a proxy for stellar mass, along with low-stellar-mass dwarf galaxies all selected from the Galaxy And Mass Assembly (GAMA) survey. The GAMA regions were selected because of the vast array of ancillary data available, including ultraviolet through to radio bands. These fields are on the celestial equator at 9, 12, and 14.5 hours, and cover a total of 144 square degrees (in GAMA-I). Higher density environments are also included with the addition of eight clusters. The clusters have spectroscopy from 2dFGRS and SDSS and photometry in regions covered by the Sloan Digital Sky Survey (SDSS) and/or VLT Survey Telescope/ATLAS. The aim is to cover a broad range in stellar mass and environment, and therefore the primary survey targets cover redshifts 0.004 < z < 0.095, magnitudes rpet < 19.4, stellar masses 107– 1012M⊙, and environments from isolated field galaxies through groups to clusters of _ 1015M⊙.

Ethanol production: energy, economic, and environmental losses.

The prime focus of ethanol production from corn is to replace the imported oil used in American vehicles, without expending more fossil energy in ethanol production than is produced as ethanol energy. In a thorough and up-to-date evaluation of all the fossil energy costs of ethanol production from corn, every step in the production and conversion process must be included. In this study, 14 energy inputs in average U.S. corn production are included. Then, in the fermentation/distillation operation, 9 more identified fossil fuel inputs are included. Some energy and economic credits are given for the by-products, including dried distillers grains (DDG). Based on all the fossil energy inputs, a total of 1.43 kcal fossil energy is expended to produced 1 kcal ethanol. When the energy value of the DDG, based on the feed value of the DDG as compared to that of soybean meal, is considered, the energy cost of ethanol production is reduced slightly, to 1.28 kcal fossil energy input per 1 kcal ethanol produced. Several proethanol investigators have overlooked various energy inputs in U.S. corn production, including farm machinery, processing machinery, and the use of hybrid corn. In other studies, unrealistic, low energy costs were attributed to such inputs as nitrogen fertilizer, insecticides, and herbicides. Controversy continues concerning the energy and economic credits that should be assigned to the by-products. The U.S. Department of Energy reports that 17.0 billion L ethanol was produced in 2005. This represents only less than 1% of total oil use in the U.S. These yields are based on using about 18% of total U.S. corn production and 18% of cornland. Because the production of ethanol requires large inputs of both oil and natural gas in production, the U.S. is importing both oil and natural gas to produce ethanol. Furthermore, the U.S. Government is spending about dollar 3 billion annually to subsidize ethanol production, a subsidy of dollar 0.79/L ethanol produced. With the subsidy, plus the cost of production, the cost of ethanol is calculated to be dollar 1.21/L. The subsidy for a liter of ethanol is 45-times greater than the subsidy per liter of gasoline. The environmental costs associated with producing ethanol are significant but have been ignored by most investigators in terms of energy and economics. The negative environmental impacts on cropland, and freshwater, as well as air pollution and public health, have yet to be carefully assessed. These environmental costs in terms of energy and economics should be calculated and included in future ethanol analyses. General concern has been expressed about taking 18% of U.S. corn, and more in the future, to produce ethanol for burning in automobiles instead of using the corn as food for the many malnourished people in the world. The World Health Organization reports that more than 3.7 billion humans are currently malnourished in the world--the largest number ever in history.

Are the Narrow-Line Regions in Active Galaxies Dusty and Radiation Pressure Dominated?

The remarkable similarity between emission spectra of narrow-line regions (NLRs) in Seyfert galaxies has long presented a mystery. In photoionization models, this similarity implies that the ionization parameter is nearly always the same, about U ~ 0.01. Here we present dusty, radiation pressure-dominated photoionization models that can provide natural physical insight into this problem. In these models, dust and the radiation pressure acting upon it provide the controlling factor in moderating the density, excitation, and surface brightness of photoionized NLR structures. Additionally, photoelectric heating by the dust is important in determining the temperature structure of the models. These models can also explain the coexistence of the low-, intermediate-, and coronal ionization zones within a single self-consistent physical structure. The radiation pressure acting on dust may also be capable of driving the fast (~3000 km s-1) outflows such as are seen in the HST observations of NGC 1068.

The nuclear superbubble of NGC 3079

We have used the Hawaii Imaging Fabry-Perot Interferometer (HIFI) at the CFH 3.6 m telescope to map H-alpha + (N II) lambda-lambda 6548, 6583 emission-line profiles across the entire edge-on, nearby SBc galaxy NGC 3079, with resolution 70 km/s and subarcsecond sampling. Blue and red long-slit spectra were obtained with the Double Spectrograph on the Palomar 5 meter telescope to provide additional emission-line diagnostics. A spectacular, line emitting bubble of diameter 13 sec (approximately 1.1 kpc) is observed immediately east of the nucleus. Its unusual gaseous excitation (e.g., (N II) lambda(6583)/H-alpha greater than 1) suggests that shocks are important. Extremely violent gas motions that range over 2000 km/s are detected across the bubble and diametrically opposite on the west side of the nucleus. Nonrotational motions are also found in the inner galaxy disk. The superbubble of NGC 3079 is the most powerful example known of a wind-blown bubble, and an excellent laboratory to study wind dynamics. The dimensions and energies of the bubble imply that is likely to be in the blowout phase and partially ruptured. The predicted rate of kinetic energy output from the central starburst appears sufficient to power most of this outflow. It is possible that a central active galactic nucleus also contributes to the outflow.

The braided jets in the spiral galaxy NGC 4258

The Hawaii Imaging Fabry-Perot Interferometer have been used to synthesize 44000 Hα and [N II] emission-line profiles at velocity resolution 68 km/s FWHM across the disk of the nearby Seyfert/LINER galaxy NGC 4258, including the prominent «four-branched jet» that extends to 10 and 5 kpc radii in the radio continuum and optical emission lines, respectively. A long-slit spectrum, which includes the emission lines Hα, [N II] λλ6548, 6583 and [S II] λλ6717, 6731, has also been obtained along the jets

Galactic-Scale Outflow and Supersonic Ram-Pressure Stripping in the Virgo Cluster Galaxy NGC 4388

The Hawaii Imaging Fabry-Perot Interferometer (HIFI) on the University of Hawaii 2.2 m telescope was used to map the Hα and [O III] λ5007 emission-line profiles across the entire disk of the edge-on Sb galaxy NGC 4388. We confirm a rich complex of highly ionized gas that extends ~4 kpc above the disk of this galaxy. Low-ionization gas associated with star formation is also present in the disk. Evidence for bar streaming is detected in the disk component and is discussed in a companion paper. Nonrotational blueshifted velocities of 50-250 km s-1 are measured in the extraplanar gas northeast of the nucleus. The brighter features in this complex tend to have more blueshifted velocities. A redshifted cloud is also detected 2 kpc southwest of the nucleus. The velocity field of the extraplanar gas of NGC 4388 appears to be unaffected by the inferred supersonic (Mach number M ≈ 3) motion of this galaxy through the ICM of the Virgo cluster. We argue that this is because the galaxy and the high-|z| gas lie behind a Mach cone with opening angle ~80°. The shocked ICM that flows near the galaxy has a velocity of ~500 km s-1 and exerts insufficient ram pressure on the extraplanar gas to perturb its kinematics. We consider several explanations of the velocity field of the extraplanar gas. Velocities, especially blueshifted velocities on the north of the galaxy, are best explained as a bipolar outflow that is tilted by >12° from the normal to the disk. The observed offset between the extraplanar gas and the radio structure may be due to buoyancy or refractive bending by density gradients in the halo gas. Velocity substructure in the outflowing gas also suggests an interaction with ambient halo gas.

The Smith cloud: H i associated with the Sgr dwarf?

ABSTRA C T The Smith high-velocity cloud (VLSR o 98 km s π1 ) has been observed at two locations in the emission lines [O III]l5007, [N II]l6548 and Ha. Both the [N II] and Ha profiles show bright cores due to the Reynolds layer, and red wings with emission extending to VLSR < 130 km s π1 . This is the first simultaneous detection of two emission lines towards a high-velocity cloud, allowing us to form the ratio of these line profiles as a function of local standard of rest (LSR) velocity. At both cloud positions, we see a clear distinction between emission at the cloud velocity, and the Reynolds layer emission (VLSR < 0). The [N II]/Ha ratio (<0:25) for the Reynolds layer is typical of the warm ionized medium. At the cloud velocity, this ratio is enhanced by a factor of 3‐4 compared to emission at rest with respect to the LSR. A moderately deep upper limit at [O III] (0.12R at 3j) was derived from our data. If the emission arises from dilute photoionization from hot young stars, the highly enhanced [N II]/Ha ratio, the [O III] non-detection and weak Ha emission (0.24‐0.30R) suggest that the Smith cloud is 26 6 4 kpc from the Sun, at a Galactocentric radius of 20 6 4 kpc. This value assumes that the emission arises from an optically thick slab, with a covering fraction of unity as seen by the ionizing photons, the orientation of which is either (a) parallel to the Galactic disc, or (b) such as to maximize the received flux from the disc. The estimated mass and size of the cloud are 4 〈 10 6 M( and 6 kpc. We discuss a possible association with the much larger Sgr dwarf, at a Galactocentric radius of 16 6 2 kpc, which lies within 358 (,12 kpc) of the Smith cloud.

Imaging spectrophotometry of ionized gas in NGC 1068. I. Kinematics of the narrow-line region

The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis. 67 refs.

The Active Jet in NGC 4258 and Its Associated Shocks

We present images and spectra of the active jet and anomalous arms on subparsec through kiloparsec scales in the LINER/Seyfert galaxy NGC 4258 (M106). New VLBA and multicon—guration VLA images show that, on 0.3¨300 pc scales, the jet in projection aligns with (1) the spin axis of the underlying accre- tion disk and (2) two radio hot spots 24A S (840 pc) and 49A N (1.7 kpc) from the nucleus. Hubble Space T elescope WFPC2 (N II) j6583 ) Ha images locate interactions between the jet and the interstellar medium (ISM). The most prominent is a pair of emission line arcs whose apices face away from the galaxy nucleus and envelop the leading edges of the radio hot spots. Ground-based (WHT) spectra with 2 resolution con—rm that the gaseous kinematics and excitation of both arcs have the spatio-kinematic Ae structure expected for jet working surfaces with a shock velocity 350 ^ 100 km s~1. The north shock is oblique and may lie in a nuclear ionization cone. The south shock shows a detached, putative Mach disk. Models suggest that the S shock is a bow shock around a jet whose progress toward us through the galaxy ISM has stalled. This is notable because the inferred out—ow axis is misaligned by D65i (in three dimensions) with the spin axis of the accretion disk. Our emission line ratios and pro—les diagnose the physical properties of the shocks, possible Mach disk, and thence the jets. The shocks lie at one end of a swath of kinematically disturbed gas that reaches back to the previously recognized spiral ii anomalous arms, ˇˇ suggesting that they are linked dynamically by precession of the central engine; although claimed elsewhere to be bar shocks, the anomalous arms are probably a fossil record of chang- ing jet activity in NGC 4258. Our results imply that the jet has recently moved a long way out of the plane of the galaxy. A deep Taurus Tunable Filter Ha image shows that discrete strands in the anom- alous arms persist to galactocentric radii of at least 4@ ((8 kpc), indicating an ongoing ISM interaction. Subject headings: galaxies: individual (NGC 4258) ¨ galaxies: ISMgalaxies: jetsshock waves

The SAMI Galaxy Survey: cubism and covariance, putting round pegs into square holes

We present a methodology for the regularization and combination of sparse sampled and irregularly gridded observations from fibre-optic multiobject integral field spectroscopy. The approach minimizes interpolation and retains image resolution on combining subpixel dithered data. We discuss the methodology in the context of the Sydney–AAO multiobject integral field spectrograph (SAMI) Galaxy Survey underway at the Anglo-Australian Telescope. The SAMI instrument uses 13 fibre bundles to perform high-multiplex integral field spectroscopy across a 1° diameter field of view. The SAMI Galaxy Survey is targeting ∼3000 galaxies drawn from the full range of galaxy environments. We demonstrate the subcritical sampling of the seeing and incomplete fill factor for the integral field bundles results in only a 10 per cent degradation in the final image resolution recovered. We also implement a new methodology for tracking covariance between elements of the resulting data cubes which retains 90 per cent of the covariance information while incurring only a modest increase in the survey data volume.