The SAMI Galaxy Survey: Early Data Release Allen, J. T.; Croom, S. M.; Konstantopoulos, I. S. ...
Monthly notices of the Royal Astronomical Society,
01/2015, Letnik:
446, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present the Early Data Release of the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. The SAMI Galaxy Survey is an ongoing integral field spectroscopic survey of ~3400 ...low-redshift (z < 0.12) galaxies, covering galaxies in the field and in groups within the Galaxy And Mass Assembly (GAMA) survey regions, and a sample of galaxies in clusters. In the Early Data Release, we publicly release the fully calibrated data cubes for a representative selection of 107 galaxies drawn from the GAMA regions, along with information about these galaxies from the GAMA catalogues. All data cubes for the Early Data Release galaxies can be downloaded individually or as a set from the SAMI Galaxy Survey website. In this paper we also assess the quality of the pipeline used to reduce the SAMI data, giving metrics that quantify its performance at all stages in processing the raw data into calibrated data cubes. The pipeline gives excellent results throughout, with typical sky subtraction residuals in the continuum of 0.9-1.2 per cent, a relative flux calibration uncertainty of 4.1 per cent (systematic) plus 4.3 per cent (statistical), and atmospheric dispersion removed with an accuracy of 0.09 arcsec, less than a fifth of a spaxel.
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.
We present the SAMI Pilot Survey, consisting of integral field spectroscopy of 106 galaxies across three galaxy clusters, Abell 85, Abell 168 and Abell 2399. The galaxies were selected by absolute ...magnitude to have M
r
< −20.25 mag. The survey, using the Sydney-AAO Multi-object Integral field spectrograph (SAMI), comprises observations of galaxies of all morphological types with 75 per cent of the sample being early-type galaxies (ETGs) and 25 per cent being late-type galaxies (LTGs). Stellar velocity and velocity dispersion maps are derived for all 106 galaxies in the sample. The λ
R
parameter, a proxy for the specific stellar angular momentum, is calculated for each galaxy in the sample. We find a trend between λ
R
and galaxy concentration such that LTGs are less concentrated higher angular momentum systems, with the fast-rotating ETGs (FRs) more concentrated and lower in angular momentum. This suggests that some dynamical processes are involved in transforming LTGs to FRs, though a significant overlap between the λ
R
distributions of these classes of galaxies implies that this is just one piece of a more complicated picture. We measure the kinematic misalignment angle, Ψ, for the ETGs in the sample, to probe the intrinsic shapes of the galaxies. We find the majority of FRs (83 per cent) to be aligned, consistent with them being oblate spheroids (i.e. discs). The slow rotating ETGs (SRs), on the other hand, are significantly more likely to show kinematic misalignment (only 38 per cent are aligned). This confirms previous results that SRs are likely to be mildly triaxial systems.
Abstract
We describe the selection of galaxies targeted in eight low-redshift clusters (APMCC0917, A168, A4038, EDCC442, A3880, A2399, A119 and A85; 0.029 < z < 0.058) as part of the Sydney-AAO ...Multi-Object Integral field spectrograph Galaxy Survey (SAMI-GS). We have conducted a redshift survey of these clusters using the AAOmega multi-object spectrograph on the 3.9-m Anglo-Australian Telescope. The redshift survey is used to determine cluster membership and to characterize the dynamical properties of the clusters. In combination with existing data, the survey resulted in 21 257 reliable redshift measurements and 2899 confirmed cluster member galaxies. Our redshift catalogue has a high spectroscopic completeness (∼94 per cent) for rpetro ≤ 19.4 and cluster-centric distances R < 2R200. We use the confirmed cluster member positions and redshifts to determine cluster velocity dispersion, R200, virial and caustic masses, as well as cluster structure. The clusters have virial masses 14.25 ≤ log(M200/M⊙) ≤ 15.19. The cluster sample exhibits a range of dynamical states, from relatively relaxed-appearing systems, to clusters with strong indications of merger-related substructure. Aperture- and point spread function matched photometry are derived from Sloan Digital Sky Survey and VLT Survey Telescope/ATLAS imaging and used to estimate stellar masses. These estimates, in combination with the redshifts, are used to define the input target catalogue for the cluster portion of the SAMI-GS. The primary SAMI-GS cluster targets have R <R200, velocities |vpec| < 3.5σ200 and stellar masses $9.5 \le {\rm log({\it M}}^*_{{\rm approx}}/$M⊙)≤12. Finally, we give an update on the SAMI-GS progress for the cluster regions.
The Smith high-velocity cloud (VLSR = 98 km s−1) has been observed at two locations in the emission lines O iiiλ5007, N iiλ6548 and Hα. Both the N ii and Hα profiles show bright cores due to the ...Reynolds layer, and red wings with emission extending to VLSR ≈ 130 km s−1. 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/Hα 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 3σ) was derived from our data. If the emission arises from dilute photoionization from hot young stars, the highly enhanced N ii/Hα ratio, the O iii non-detection and weak Hα emission (0.24–0.30R) suggest that the Smith cloud is 26 ± 4 kpc from the Sun, at a Galactocentric radius of 20 ± 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 × 106 M⊙ and 6 kpc. We discuss a possible association with the much larger Sgr dwarf, at a Galactocentric radius of 16 ± 2 kpc, which lies within 35° (∼12 kpc) of the Smith cloud.
The Ringberg Standards for NGC 1068 Bland-hawthorn, J; Gallimore, Jf; Tacconi, Lj ...
Astrophysics and space science,
02/1997, Letnik:
248, Številka:
1-2
Journal Article
Recenzirano
At the end of three days' spirited discussion of the type 2 Seyfert galaxy NGC 1068, what do we think we understand about this object? New observations -- particularly in the infrared and radio -- ...are helping to resolve old problems, while drawing attention to new ones. It appears that NGC 1068 is a relatively normal spiral galaxy in which large-scale gravitational disturbances are funneling matter into the nucleus. A collimated outflow disturbs the interstellar medium out to kiloparsec scales, but the nucleus itself is hidden behind an opaque screen. Radio observations have now pierced the screen, and suggest that at the center of it all, a 10-20 million solar mass black hole is accreting at close to its Eddington limit.PUBLICATION ABSTRACT
We describe the selection of galaxies targeted in eight low redshift clusters (APMCC0917, A168, A4038, EDCC442, A3880, A2399, A119 and A85; \(0.029 < z < 0.058\)) as part of the Sydney-AAO ...Multi-Object integral field Spectrograph Galaxy Survey (SAMI-GS). We have conducted a redshift survey of these clusters using the AAOmega multi-object spectrograph on the 3.9m Anglo-Australian Telescope. The redshift survey is used to determine cluster membership and to characterise the dynamical properties of the clusters. In combination with existing data, the survey resulted in 21,257 reliable redshift measurements and 2899 confirmed cluster member galaxies. Our redshift catalogue has a high spectroscopic completeness (\(\sim 94\%\)) for \(r_{\rm petro} \leq 19.4\) and clustercentric distances \(R< 2\rm{R}_{200}\). We use the confirmed cluster member positions and redshifts to determine cluster velocity dispersion, \(\rm{R}_{200}\), virial and caustic masses, as well as cluster structure. The clusters have virial masses \(14.25 \leq {\rm log }({\rm M}_{200}/\rm{M}_{\odot}) \leq 15.19\). The cluster sample exhibits a range of dynamical states, from relatively relaxed-appearing systems, to clusters with strong indications of merger-related substructure. Aperture- and PSF-matched photometry are derived from SDSS and VST/ATLAS imaging and used to estimate stellar masses. These estimates, in combination with the redshifts, are used to define the input target catalogue for the cluster portion of the SAMI-GS. The primary SAMI-GS cluster targets have \(R< \rm{R}_{200}\), velocities \(|v_{\rm pec}| < 3.5\sigma_{200}\) and stellar masses \(9.5 \leq {\rm log(M}^*_{approx}/\rm{M}_{\odot}) \leq 12\). Finally, we give an update on the SAMI-GS progress for the cluster regions.
•Epigenetic regulation of mitochondrial DNA (mtDNA) (mitoepigenetics) is an emerging and fast developing field of research.•Cancer cells contain oxidative stress-mediated defects in mtDNA repair ...system, nucleoid-based organization, and mitoepigenetic regulation.•Dysbalanced mitoepigenetics and adverse regulation of oxidative phosphorylation (OXPHOS) can efficiently facilitate cancer cell survival.•Anti-cancer effects of several mitochondria-targeting agents warrant further testing in breast cancers.•Crosstalk mechanism between mitoepigenetics and cancer-associated mtDNA mutations is a promising therapy target in breast cancers.
Epigenetic regulation of mitochondrial DNA (mtDNA) is an emerging and fast-developing field of research. Compared to regulation of nucler DNA, mechanisms of mtDNA epigenetic regulation (mitoepigenetics) remain less investigated. However, mitochondrial signaling directs various vital intracellular processes including aerobic respiration, apoptosis, cell proliferation and survival, nucleic acid synthesis, and oxidative stress. The later process and associated mismanagement of reactive oxygen species (ROS) cascade were associated with cancer progression. It has been demonstrated that cancer cells contain ROS/oxidative stress-mediated defects in mtDNA repair system and mitochondrial nucleoid protection. Furthermore, mtDNA is vulnerable to damage caused by somatic mutations, resulting in the dysfunction of the mitochondrial respiratory chain and energy production, which fosters further generation of ROS and promotes oncogenicity. Mitochondrial proteins are encoded by the collective mitochondrial genome that comprises both nuclear and mitochondrial genomes coupled by crosstalk. Recent reports determined the defects in the collective mitochondrial genome that are conducive to breast cancer initiation and progression. Mutational damage to mtDNA, as well as its overproliferation and deletions, were reported to alter the nuclear epigenetic landscape. Unbalanced mitoepigenetics and adverse regulation of oxidative phosphorylation (OXPHOS) can efficiently facilitate cancer cell survival. Accordingly, several mitochondria-targeting therapeutic agents (biguanides, OXPHOS inhibitors, vitamin-E analogues, and antibiotic bedaquiline) were suggested for future clinical trials in breast cancer patients. However, crosstalk mechanisms between altered mitoepigenetics and cancer-associated mtDNA mutations remain largely unclear. Hence, mtDNA mutations and epigenetic modifications could be considered as potential molecular markers for early diagnosis and targeted therapy of breast cancer. This review discusses the role of mitoepigenetic regulation in cancer cells and potential employment of mtDNA modifications as novel anti-cancer targets.
The radio jet axis of NGC 1068 is characterised by energetic activity from x-ray to radio wavelengths. Detailed kinematic and polarization studies have shown that this activity is confined to bipolar ...cones centered on the AGN which intersect the plane of the disk. Thus, molecular clouds at 1 kpc distance along this axis are an important probe of the nuclear ionizing luminosity and spectrum. Extended 10.8µm emission coincident with the clouds is reasonably understood by dust heated to high temperatures by the nuclear radiation field. This model predicts that the nuclear spectrum is quasar-like (power law + blue excess) with a luminosity 2-5 times higher than inferred by Pier et al. (1994). Consequently, there is little or no polyaromatic hydrocarbon (PAH) emission associated with the radio-axis molecular clouds. We review this model in the light of new observations. A multi-waveband collage is included to illustrate the possible orientations of the double cones to our line of sight and the galaxian plane.PUBLICATION ABSTRACT
Atopic disease, including atopic dermatitis (eczema), allergy and asthma, has increased in frequency in recent decades and now affects ∼20% of the population in the developed world. Twin and family ...studies have shown that predisposition to atopic disease is highly heritable. Although most genetic studies have focused on immunological mechanisms, a primary epithelial barrier defect has been anticipated. Filaggrin is a key protein that facilitates terminal differentiation of the epidermis and formation of the skin barrier. Here we show that two independent loss-of-function genetic variants (R510X and 2282del4) in the gene encoding filaggrin (FLG) are very strong predisposing factors for atopic dermatitis. These variants are carried by ∼9% of people of European origin. These variants also show highly significant association with asthma occurring in the context of atopic dermatitis. This work establishes a key role for impaired skin barrier function in the development of atopic disease.
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