13 research outputs found
Mortality characteristics in sumadija district from 2010 – 2017
Mortality rate represents a number of deaths on a particular territory per time unit. There are general and specific mortalities. The aims at analysing the characteristics of mortality in Sumadija District for the time period ranging from 2010 – 2017. The study includes all death cases in the District of Sumadija in period 2010-2017, 34681 cases. The data are described and analysed with χ² test and linear trend. The trend analysis does not indicate any significant vari-ations during the given time span. The gender analysis re-veals that there is a significantly higher number of deceased persons among male population (52.2%, 47.8%, р<0.05). The average age of the deceased females (76.2±13.4) was higher than the average age of males (73.8±14.1) (р<0.05). The cause-specific analysis shows that natural causes of death dominate absolutely (96.5%) over violent deaths (2.7%) and undetermined causes (0.8%). The distribution of death causes according to ICD 10 shows that the most frequent causes of death are heart and blood vessel diseases, respiratory and neoplasm diseases. The life expectancy of the inhabitants of Sumadija District is increasing over time. There was a slight decrease in the mortality rates during the observed time period. The highest number of the deceased people is 65 or more years old. Men have higher mortality rates throughout their lives. Natural death and non-communicable diseases are dominant. The most common causes of death are heart and blood vessels diseases, in women, and respiratory and neo-plasm diseases, in men
A measurement of galaxy halo mass from the surrounding H i Lyα absorption
We measure the dark matter halo masses of 〈z〉 ≈ 2.36 UV colour-selected star-forming galaxies by matching the observed median H I Lyα absorption around them, as observed in the spectra of background QSOs, to the absorption around haloes above a given mass in cosmological simulations. Focusing on transverse separations 0–2 proper Mpc (pMpc) and line-of-sight separations 154–616 km s^(−1), we find a minimum halo mass of log_(10)M_(min)/M⊙ = 11.6 ± 0.2, which is in good agreement with published halo mass estimates from clustering analyses. We verified that the measured halo mass is insensitive to a change in the cosmological parameters (Wilkinson Microwave Anisotropy Probe 1 versus Wilkinson Microwave Anisotropy Probe 3) and to the inclusion of strong AGN feedback. One unique strength of this method is that it can be used in narrow field galaxy–QSO surveys, i.e. ≈30 × 30 arcsec. In addition, we find that the observed anisotropy in the 2D H I Lyα absorption distribution on scales of 1.5–2 pMpc is consistent with being a consequence of large-scale gas infall into the potential wells occupied by galaxies
Calibrating Galaxy Redshifts Using Absorption by the Surrounding Intergalactic Medium
Rest-frame UV spectral lines of star-forming galaxies are systematically
offset from the galaxies' systemic redshifts, probably because of large-scale
outflows. We calibrate galaxy redshifts measured from rest-frame UV lines by
utilizing the fact that the mean HI Ly-alpha absorption profiles around the
galaxies, as seen in spectra of background objects, must be symmetric with
respect to the true galaxy redshifts if the galaxies are oriented randomly with
respect to the lines of sight to the background objects. We use 15 QSOs at
z~2.5-3 and more than 600 foreground galaxies with spectroscopic redshifts at
z~1.9-2.5. All galaxies are within 2 Mpc proper from the lines of sight to the
background QSOs. We find that LyA emission and ISM absorption redshifts require
systematic shifts of v_LyA=-295(+35)(-35) km/s and v_ISM=145(+70)(-35) km/s.
Assuming a Gaussian distribution, we put 1-sigma upper limits on possible
random redshift offsets of <220 km/s for LyA and <420 km/s for ISM redshifts.
For the small subset (<10%) of galaxies for which near-IR spectra have been
obtained, we can compare our results to direct measurements based on nebular
emission lines which we confirm to mark the systemic redshifts. While our v_ISM
agrees with the direct measurements, our v_LyA is significantly smaller.
However, when we apply our method to the near-IR subsample which is
characterized by slightly different selection effects, the best-fit velocity
offset comes into agreement with the direct measurement. This confirms the
validity of our approach, and implies that no single number appropriately
describes the whole population of galaxies, in line with the observation that
the line offset depends on galaxy spectral morphology. This method provides
accurate redshift calibrations and will enable studies of circumgalactic matter
around galaxies for which rest-frame optical observations are not available.Comment: 7 pages, 3 figures, accepted for publication in MNRA
The Gaseous Environment of High-z Galaxies: Precision Measurements of Neutral Hydrogen in the Circumgalactic Medium of z ~ 2-3 Galaxies in the Keck Baryonic Structure Survey
We present results from the Keck Baryonic Structure Survey (KBSS), a unique
spectroscopic survey designed to explore the connection between galaxies and
intergalactic baryons. The KBSS is optimized for the redshift range z ~ 2-3,
combining S/N ~ 100 Keck/HIRES spectra of 15 hyperluminous QSOs with densely
sampled galaxy redshift surveys surrounding each QSO sightline. We perform
Voigt profile decomposition of all 6000 HI absorbers within the full Lya forest
in the QSO spectra. Here we present the distribution, column density,
kinematics, and absorber line widths of HI surrounding 886 star-forming
galaxies with 2.0 < z < 2.8 and within 3 Mpc of a QSO sightline. We find that
N_HI and the multiplicity of HI components increase rapidly near galaxies. The
strongest HI absorbers within ~ 100 physical kpc of galaxies have N_HI ~ 3 dex
higher than those near random locations in the IGM. The circumgalactic zone of
most enhanced HI absorption (CGM) is found within 300 kpc and 300 km/s of
galaxies. Nearly half of absorbers with log(N_HI) > 15.5 are found within the
CGM of galaxies meeting our photometric selection, while their CGM occupy only
1.5% of the cosmic volume. The spatial covering fraction, multiplicity of
absorption components, and characteristic N_HI remain elevated to transverse
distances of 2 physical Mpc. Absorbers with log(N_HI) > 14.5 are tightly
correlated with the positions of galaxies, while absorbers with lower N_HI are
correlated only on Mpc scales. Redshift anisotropies on Mpc scales indicate
coherent infall toward galaxies, while on scales of ~100 physical kpc peculiar
velocities of 260 km/s are indicated. The median Doppler widths of absorbers
within 1-3 virial radii of galaxies are ~50% larger than randomly chosen
absorbers of the same N_HI, suggesting higher gas temperatures and/or increased
turbulence likely caused by accretion shocks and/or galactic winds.Comment: Accepted to Ap
The Structure and Kinematics of the Circumgalactic Medium from Far-ultraviolet Spectra of z ≃ 2-3 Galaxies
We present new results on the kinematics and spatial distribution of metal-enriched gas within ~125 kpc of star-forming ("Lyman break") galaxies at redshifts 2 ≲ z ≲ 3. In particular, we focus on constraints provided by the rest-frame far-ultraviolet (far-UV) spectra of faint galaxies, and demonstrate how galaxy spectra can be used to obtain key spatial and spectral information more efficiently than possible with QSO sightlines. Using a sample of 89 galaxies with z = 2.3 ± 0.3 and with both rest-frame far-UV and Hα spectra, we re-calibrate the measurement of accurate galaxy systemic redshifts using only survey-quality rest-UV spectra. We use the velocity-calibrated sample to investigate the kinematics of the galaxy-scale outflows via the strong interstellar (IS) absorption lines and Lyα emission (when present), as well as their dependence on other physical properties of the galaxies. We construct a sample of 512 close (1"-15") angular pairs of z ~ 2-3 galaxies with redshift differences indicating a lack of physical association. Sightlines to the background galaxies provide new information on the spatial distribution of circumgalactic gas surrounding the foreground galaxies. The close pairs sample galactocentric impact parameters 3-125 kpc (physical) at = 2.2, providing for the first time a robust map of cool gas as a function of galactocentric distance for a well-characterized population of galaxies. We propose a simple model of circumgalactic gas that simultaneously matches the kinematics, depth, and profile shape of IS absorption and Lyα emission lines, as well as the observed variation of absorption line strength (H I and several metallic species) versus galactocentric impact parameter. Within the model, cool gas is distributed symmetrically around every galaxy, accelerating radially outward with v_(out)(r) increasing with r (i.e., the highest velocities are located at the largest galactocentric distances r). The inferred radial dependence of the covering fraction of cool gas (which modulates the absorption line strength) is f_c(r) ∝ r^(–γ) with 0.2 ≲ γ ≲ 0.6 depending on transition. We discuss the results of the observations in the context of "cold accretion," in which cool gas is accreting via filamentary streams directly onto the central regions of galaxies. At present, we find little observational evidence for cool infalling material, while evidence supporting the large-scale effects of superwind outflows is strong. This "pilot" study using faint galaxy spectra demonstrates the potential of using galaxies to trace baryons within galaxies, in the circumgalactic medium, and ultimately throughout the intergalactic medium
The Structure and Kinematics of the Circum-Galactic Medium from Far-UV Spectra of z~2-3 Galaxies
We present new results on the kinematics and spatial distribution of
metal-enriched gas within 125 kpc (physical) of Lyman Break galaxies at
redshifts z~2-3. In particular, we demonstrate how rest-UV galaxy spectra can
be used to obtain key spatial and spectral information more efficiently than
possible with QSO sightlines. After recalibrating the measurement of galaxy
systemic redshifts from their UV spectra, we investigate the kinematics of
galaxy-scale outflows via the strong interstellar (IS) absorption and Lya
emission lines (when present), as well as their dependence on other physical
properties of the galaxies. We construct a sample of 512 close (1-15 arcsec)
angular pairs of z~2-3 LBGs in which the spectra background galaxies probe the
circumgalactic gas surrrounding those in the foreground. The close pairs,
together with spectra of the foreground galaxies themselves, sample
galactocentric impact parameters b=0-125 kpc (physical) at =2.2. The
ensemble provides a spatial map of cool gas as a function of galactocentric
distance for a well-characterized population of galaxies. We propose a simple
model that simultaneously matches the kinematics, depth, and profile shape of
IS absorption and Lya emission lines, as well as the observed variation of
absorption line strength (of HI, CII, CIV, SiII, SiIV) versus galactocentric
impact parameter. We discuss the results of the observations in the context of
"cold accretion", in which cool gas accretes via filamentary streams directly
onto the central regions of galaxies. At present, we find little observational
support for cool infalling material, whereas evidence supporting the
large-scale effects of outflows is strong. Reconciling theory and observation
on the subject of gas flows into and out of forming galaxies seems necessary.Comment: To appear in ApJ; minor revisions to match journal version; added 1
figure, several references, and a subsection discussing the inferred rate of
gas outflow into the IG
Neutral hydrogen optical depth near star-forming galaxies at z~2.4 in the Keck Baryonic Structure Survey
[Abridged] We study the interface between galaxies and the intergalactic
medium by measuring the absorption by neutral hydrogen in the vicinity of
star-forming galaxies at z~2.4. Our sample consists of 679 rest-frame-UV
selected galaxies with spectroscopic redshifts that have impact parameters < 2
(proper) Mpc to the line of sight of one of 15 bright, background QSOs. We
present the first 2-D maps of the absorption around galaxies, plotting the
median Ly-a pixel optical depth as a function of transverse and line of sight,
LOS, separation from galaxies. The median optical depth, and hence the median
density of atomic hydrogen, drops by more than an order of magnitude around 100
kpc, which is similar to the virial radius of the halos thought to host the
galaxies. The median remains enhanced (>3 sigma level) out to at least 2.8 Mpc
(i.e. > 9 comoving Mpc). Within 100 (200) kpc, and over \pm 165 km/s, the
covering fraction of gas with Ly-a optical depth greater than unity is
100(+0)(-32)% (86(+14)(-18)%). Absorbers with tau(Ly-a)> 0.1 are typically
closer to galaxies than random. The mean galaxy overdensity around absorbers
increases with the optical depth and also as the length scale over which the
galaxy overdensity is evaluated is decreased. Absorbers with tau(Ly-a)~1 reside
in regions where the galaxy number density is close to the cosmic mean on
scales > 0.25 Mpc. We detect two types of redshift space anisotropies. On
scales < 200 km/s, or < 1 Mpc, the absorption is stronger along the LOS than in
the transverse direction. This "finger of God" effect may be partly due to
redshift errors, but is probably dominated by gas motions within or very close
to the halos. On the other hand, on scales of 1.4 - 2.0 Mpc the absorption is
compressed along the LOS (>3 sigma significance), which we attribute to
large-scale infall (i.e. the Kaiser effect).Comment: Accepted for publication in the ApJ (replaced with revised version
incorporating referee's comments