295 research outputs found
The counterrotating core and the black hole mass of IC1459
The E3 giant elliptical galaxy IC1459 is the prototypical galaxy with a fast
counterrotating stellar core. We obtained one HST/STIS long-slit spectrum along
the major axis of this galaxy and CTIO spectra along five position angles. We
present self-consistent three-integral axisymmetric models of the stellar
kinematics, obtained with Schwarzschild's numerical orbit superposition method.
We study the dynamics of the kinematically decoupled core (KDC) in IC1459 and
we find it consists of stars that are well-separated from the rest of the
galaxy in phase space. The stars in the KDC counterrotate in a disk on orbits
that are close to circular. We estimate that the KDC mass is ~0.5% of the total
galaxy mass or ~3*10^9 Msun. We estimate the central black hole mass M_BH of
IC1459 independently from both its stellar and its gaseous kinematics. Some
complications probably explain why we find rather discrepant BH masses with the
different methods. The stellar kinematics suggest that M_BH = (2.6 +/-
1.1)*10^9 Msun (3 sigma error). The gas kinematics suggests that M_BH ~
3.5*10^8 Msun if the gas is assumed to rotate at the circular velocity in a
thin disk. If the observed velocity dispersion of the gas is assumed to be
gravitational, then M_BH could be as high as ~1.0*10^9 Msun. These different
estimates bracket the value M_BH = (1.1 +/- 0.3)*10^9 Msun predicted by the
M_BH-sigma relation. It will be an important goal for future studies to assess
the reliability of black hole mass determinations with either technique. This
is essential if one wants to interpret the correlation between the BH mass and
other global galaxy parameters (e.g. velocity dispersion) and in particular the
scatter in these correlations (believed to be only ~0.3 dex). [Abridged]Comment: 51 pages, LaTeX with 19 PostScript figures. Revised version, with
three new figures and data tables. To appear in The Astrophysical Journal,
578, 2002 October 2
Restorative surgery after colectomy for ulcerative colitis in England and Sweden:observations from a comparison of nationwide cohorts
WFPC2 Observations of the Cooling Flow Elliptical in Abell 1795
We present WFPC2 images of the core of the cooling flow cD galaxy in Abell
1795. An irregular, asymmetric dust lane extends 7 \h75 kpc in projection to
the north-northwest. The dust shares the morphology observed in the H
and excess UV emission. We see both diffuse and knotty blue emission around the
dust lane, especially at the ends. The dust and emission features lie on the
edge of the radio lobes, suggesting star formation induced by the radio source
or the deflection of the radio jets off of pre-existing dust and gas. We
measure an apparent R significantly less than 3.1, implying that the
extinction law is not Galactic in the dust lane, or the presence of line
emission which is proportional to the extinction. The dust mass is at least
2 M\solar\ and is more likely to be 6.5 M\solar.Comment: 14 pages, LaTeX, Figure 4 included, Postscript Figs. 1-3 available at
ftp://astro.nmsu.edu/pub/JASON/A1795/, accepted for publication in ApJ
Letter
Interactive Effects of Climate Change with Nutrients, Mercury, and Freshwater Acidification on Key Taxa in the North Atlantic Landscape Conservation Cooperative Region
The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a publicâprivate partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC regionspecific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomenaâfreshwater acidification and eutrophication. We also prepared taxa case studies on GCCand GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region\u27s estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC
WFPC2 observations of the cooling flow elliptical in Abell 1795
We present WFPC2 images of the core of the cooling flow cD galaxy in Abell 1795. An irregular, asymmetric dust lane extends 7 h^(-1)/75 kpc in projection to the north-northwest. The dust shares the morphology observed in the Ha and excess UV emission. We see both diffuse and knotty blue emission around the dust lane, especially at the ends. The dust and emission features lie on the edge of the radio lobes, suggesting star formation induced by the radio source or the deflection of the radio jets off of preexisting dust and gas. We measure an apparent R(V) significantly less than 3.1, implying that the extinction law is not Galactic in the dust lane, or the presence of line emission that is proportional to the extinction. The dust mass is at least 2 x 10^5 h^(-2)/75 M_â and is more likely to be 6.5 x 10^5 h^(-2)/75 M_â
The impact of preâoperative intravenous iron on quality of life after colorectal cancer surgery: outcomes from the intravenous iron in colorectal cancerâassociated anaemia (IVICA) trial
Anaemia is associated with a reduction in quality of life, and is common in patients with colorectal cancer . Werecently reported thefindings of the intravenous iron in colorectal cancer-associated anaemia (IVICA) trialcomparing haemoglobin levels and transfusion requirements following intravenous or oral iron replacement inanaemic colorectal cancer patients undergoing elective surgery. In this follow-up study, we compared theefficacy of intravenous and oral iron at improving quality of life in this patient group. We conducted amulticentre, open-label randomised controlled trial. Anaemic colorectal cancer patients were randomlyallocated at least two weeks pre-operatively, to receive either oral (ferrous sulphate) or intravenous (ferriccarboxymaltose) iron. We assessed haemoglobin and quality of life scores at recruitment, immediately beforesurgery and at outpatient review approximately three months postoperatively, using the Short Form 36,EuroQoL 5-dimension 5-level and Functional Assessment of Cancer TherapyâAnaemia questionnaires. Werecruited 116 anaemic patients across seven UK centres (oral iron n=61 (53%), and intravenous iron n=55(47%)). Eleven quality of life components increased by a clinically significant margin in the intravenous irongroup between recruitment and surgery compared with one component for oral iron. Median (IQR [range])visual analogue scores were significantly higher with intravenous iron at a three month outpatient review (oraliron 70, (60â85 [20â95]); intravenous iron 90 (80â90 [50â100]), p=0.001). The Functional Assessment ofCancer TherapyâAnaemia score comprises of subscales related to cancer, fatigue and non-fatigue itemsrelevant to anaemia. Median outpatient scores were higher, and hence favourable, for intravenous iron on theFunctional Assessment of Cancer TherapyâAnaemia subscale (oral iron 66 (55â72 [23â80]); intravenous iron 71(66â77 [46â80]); p=0.002), Functional Assessment of Cancer TherapyâAnaemia trial outcome index (oral iron108 (90â123 [35â135]); intravenous iron 121 (113â124 [81â135]); p=0.003) and Functional Assessment ofCancer TherapyâAnaemia total score (oral iron 151 (132â170 [69â183]); intravenous iron 168 (160â174 [125â186]); p=0.005). Thesefindings indicate that intravenous iron is more efficacious at improving quality of lifescores than oral iron in anaemic colorectal cancer patients
Youth futures and a masculine development ethos in the regional story of Uttarakhand
Research on the Uttarakhand region, which became a new state in 2000, has focused largely on agrarian livelihoods, religious rituals, development demands, ecological politics and the role of women in regional social movements. This essay discusses another dimension of the regional imaginaryâthat of a masculine development ethos. Based on ethnographic research and print media sources, this essay focuses on stories, politics, mobilities and imaginations of young men in the years immediately after the achievement of statehood. Despite increased outmigration of youth in search of employment, many young men expressed the dream of maintaining livelihoods in the familiar towns and rural spaces of Uttarakhand, describing their home region as a source of power and agency. In rallies and in print media, young (mostly upper caste) men expressed their disillusionment with the government and the promises of statehood, arguing that their aspirations for development and employment were left unfulfilled. Gendered stories of the region, told in Hindi in rallies and print media, contained references to local places, people and historical events and were produced through local connections and know-how, fostering a regional youth politics. The article argues that Uttarakhand as a region is shaped by the politics of local actors as well as embodied forms of aspiration, affiliation and mobility.IS
Kinematics of Ten Early-Type Galaxies from HST and Ground-Based Spectroscopy
We present stellar kinematics for a sample of 10 early-type galaxies observed
using the STIS aboard the Hubble Space Telescope, and the Modular Spectrograph
on the MDM Observatory 2.4-m telescope. The spectra are used to derive
line-of-sight velocity distributions (LOSVDs) of the stars using a Maximum
Penalized Likelihood method. We use Gauss-Hermite polynomials to parameterize
the LOSVDs and find predominantly negative h4 values (boxy distributions) in
the central regions of our galaxies. One galaxy, NGC 4697, has significantly
positive central h4 (high tail weight). The majority of galaxies have a central
velocity dispersion excess in the STIS kinematics over ground-based velocity
dispersions. The galaxies with the strongest rotational support, as quantified
with v_MAX/sigma_STIS, have the smallest dispersion excess at STIS resolution.
The best-fitting, general, axisymmetric dynamical models (described in a
companion paper) require black holes in all cases, with masses ranging from
10^6.5 to 10^9.3 Msun. We replot these updated masses on the BH/sigma relation,
and show that the fit to only these 10 galaxies has a slope consistent with the
fits to larger samples. The greatest outlier is NGC 2778, a dwarf elliptical
with relatively poorly constrained black hole mass. The two best candidates for
pseudobulges, NGC 3384 and 7457, do not deviate significantly from the
established relation between black hole and sigma. Neither do the three
galaxies which show the most evidence of a recent merger, NGC 3608, 4473, and
4697.Comment: 43 pages, accepted for publication in the Astrophysical Journal, high
resolution version found at http://hoku.as.utexas.edu/~gebhardt/pinkney.p
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