Abstract
In this empirical work, we aim to quantify the systematic uncertainties in stellar-mass (
M
⋆
) estimates made from spectral energy distribution (SED) fitting through stellar population ...synthesis (SPS) for galaxies in the local Universe by using the dynamical mass (
M
dyn
) estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high-dimensional space of galaxy properties; including size (
R
e
), velocity dispersion (
σ
e
), surface brightness (
I
e
), mass-to-light ratio (
M
⋆
/
L
), rest-frame color, Sérsic index (
n
), and dynamical mass (
M
dyn
), and accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in
M
⋆
/
M
dyn
is driven by
σ
e
, Sérsic index and color. We use these parameters to calibrate an SED-independent
M
⋆
estimator,
M
ˆ
⋆
. We find the random scatter of the relation
M
⋆
−
M
ˆ
⋆
to be 0.108 dex and 0.147 dex for quiescent and star-forming galaxies, respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, and star formation rate) and spectral indices (H
α
, H
δ
, and
D
n
4000). For quiescent galaxies, ∼65% of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only ∼13% of the scatter. These results leave us with remaining unmodelled scatters of 0.055 dex and 0.122 dex for quiescent and star-forming galaxies, respectively. This can be interpreted as a conservative limit on the precision in
M
⋆
that can be achieved via simple SPS modeling.
ABSTRACT
In Galaxy And Mass Assembly Data Release 4 (GAMA DR4), we make available our full spectroscopic redshift sample. This includes 248 682 galaxy spectra, and, in combination with earlier ...surveys, results in 330 542 redshifts across five sky regions covering ∼250 deg2. The redshift density, is the highest available over such a sustained area, has exceptionally high completeness (95 per cent to rKiDS = 19.65 mag), and is well-suited for the study of galaxy mergers, galaxy groups, and the low redshift (z < 0.25) galaxy population. DR4 includes 32 value-added tables or Data Management Units (DMUs) that provide a number of measured and derived data products including GALEX, ESO KiDS, ESO VIKING, WISE, and HerschelSpace Observatory imaging. Within this release, we provide visual morphologies for 15 330 galaxies to z < 0.08, photometric redshift estimates for all 18 million objects to rKiDS ∼ 25 mag, and stellar velocity dispersions for 111 830 galaxies. We conclude by deriving the total galaxy stellar mass function (GSMF) and its sub-division by morphological class (elliptical, compact-bulge and disc, diffuse-bulge and disc, and disc only). This extends our previous measurement of the total GSMF down to 106.75 M$_{\odot } \, h_{70}^{-2}$ and we find a total stellar mass density of ρ* = (2.97 ± 0.04) × 108 M$_{\odot } \, h_{70}$ Mpc−3 or $\Omega _*=(2.17 \pm 0.03) \times 10^{-3} \, h_{70}^{-1}$. We conclude that at z < 0.1, the Universe has converted 4.9 ± 0.1 per cent of the baryonic mass implied by big bang Nucleosynthesis into stars that are gravitationally bound within the galaxy population.
•Oscillating Algol type binary EW Boo’s light and radial velocity curves were obtained.•Light and radial velocity curves were simultaneously analyzed.•Absolute parameters of the system were ...derived.•Frequency analysis was performed on the residual light curves.•Multi frequency fit to the data was performed on the residual light curves.
We obtained the physical and geometrical parameters of the EW Boo system, which exhibits short period and small amplitude pulsations as well as brightness variations due to orbital motion of components. Towards this end we carried out photometric observations at Ankara University Kreiken Observatory (AUKO) as well as spectroscopic observations at TUBITAK National Observatory (TNO). The light and radial velocity curves obtained from these observations have been simultaneously analyzed with PHOEBE and the absolute parameters of the system along with the geometric parameters of the components have been determined. Using model light curves of EW Boo, light curve regions in which the pulsations are active have been determined and as a result of analyses performed in the frequency region, characteristic parameters of pulsations have been obtained. We find that the results are compatible with current parameters of similar systems in the literature. The evolutionary status of the components is propounded and discussed.
In this work, we calculated the sizes of unresolved X-ray emission regions in three gravitationally lensed radio-loud quasars, B 1422+231, MG J0414+0534, and Q 0957+561, using a combination of ...imaging and spectral analysis on the X-ray data taken from the Chandra X-Ray Observatory. We tentatively detected FeK emission lines in MG J0414+0534 and Q 0957+561 with over 95% significance, whereas, we did not significantly detect FeK emission in B 1422+231. We constructed differential microlensing light curves from absorption corrected count rates. We subsequently performed a microlensing analysis on the X-ray microlensing light curves to measure the X-ray source sizes in rest frame soft (0.83-3.6 keV), hard (3.6-21.8 keV), and full (0.83-21.8 keV) bands, based on either Bayesian or maximum likelihood probabilities. For B 1422+231, sizes from the two methods are consistent with each other, (Bayesian), 11.81 3.75 (maximum likelihood), where . However, for MG J0414+0534 and Q 0957+561, the two methods yield substantially different results suggesting that more frequently sampled data with better signal-to-noise ratio are needed to measure the source size for these two objects. Comparing the acquired size values with the radio-quiet sample in the literature we found that our results are consistent with X-ray source size scaling approximately as RX ∝ MBH with the mass of the central supermassive black hole. Our Bayesian analysis results also indicate that radio-loud quasars tend to have larger unresolved X-ray emission sizes compared to the radio-quiet ones, suggesting a more prominent jet contribution.
Empirical correlations connecting starlight to galaxy dynamics (e.g., the fundamental plane (FP) of elliptical/quiescent galaxies and the Tully--Fisher relation of spiral/star-forming galaxies) ...provide cosmology-independent distance estimation and are central to local Universe cosmology. In this work, we introduce the mass hyperplane (MH), which is the stellar-to-dynamical mass relation \((M_\star/M_\mathrm{dyn})\) recast as a linear distance indicator. Building on recent FP studies, we show that both star-forming and quiescent galaxies follow the same empirical MH, then use this to measure the peculiar velocities (PVs) for a sample of 2496 galaxies at \(z<0.12\) from GAMA. The limiting precision of MH-derived distance/PV estimates is set by the intrinsic scatter in size, which we find to be \(\approx\)0.1~dex for both quiescent and star-forming galaxies (when modeled independently) and \(\approx\)0.11~dex when all galaxies are modeled together; showing that the MH is as good as the FP. To empirically validate our framework and distance/PV estimates, we compare the inferred distances to groups as derived using either quiescent or star-forming galaxies. A good agreement is obtained with no discernible bias or offset, having a scatter of \(\approx\)0.05~dex \(\approx\)12\% in distance. Further, we compare our PV measurements for the quiescent galaxies to the previous PV measurements of the galaxies in common between GAMA and the Sloan Digital Sky Survey (SDSS), which shows similarly good agreement. Finally, we provide comparisons of PV measurements made with the FP and the MH, then discuss possible improvements in the context of upcoming surveys such as the 4MOST Hemisphere Survey (4HS).
In this empirical work, we aim to quantify the systematic uncertainties in stellar mass \((M_\star)\) estimates made from spectral energy distribution (SED) fitting through stellar population ...synthesis (SPS), for galaxies in the local Universe, by using the dynamical mass \((M_\text{dyn})\) estimator as an SED-independent check on stellar mass. We first construct a statistical model of the high dimensional space of galaxy properties; size \((R_e)\), velocity dispersion \((\sigma_e)\), surface brightness \((I_e)\), mass-to-light ratio \((M_\star/L)\), rest-frame colour, Sérsic index \((n)\) and dynamical mass \((M_\text{dyn})\); accounting for selection effects and covariant errors. We disentangle the correlations among galaxy properties and find that the variation in \(M_\star/M_\text{dyn}\) is driven by \(\sigma_e\), Sérsic index and colour. We use these parameters to calibrate an SED-independent \(M_\star\) estimator, \(\hat{M}_\star\). We find the random scatter of the relation \(M_\star-\hat{M}_\star\) to be \(0.108\text{dex}\) and \(0.147\text{dex}\) for quiescent and star-forming galaxies respectively. Finally, we inspect the residuals as a function of SPS parameters (dust, age, metallicity, star formation rate) and spectral indices (H\(\alpha\), H\(\delta\), \(D_n4000)\). For quiescent galaxies, \(\sim65\%\) of the scatter can be explained by the uncertainty in SPS parameters, with dust and age being the largest sources of uncertainty. For star-forming galaxies, while age and metallicity are the leading factors, SPS parameters account for only \(\sim13\%\) of the scatter. These results leave us with remaining unmodelled scatters of \(0.055\text{dex}\) and \(0.122\text{dex}\) for quiescent and star-forming galaxies respectively. This can be interpreted as a conservative limit on the precision in \(M_\star\) that can be achieved via simple SPS-modelling.
In this work, we calculated the sizes of unresolved X-ray emission regions in three gravitationally lensed radio-loud quasars, B\,1422+231, MG\,J0414+0534 and Q\,0957+561, using a combination of ...imaging and spectral analysis on the X-ray data taken from the \textit{Chandra X-Ray Observatory}. We tentatively detected FeK\(\alpha\) emission lines in MG\,J0414+0534 and Q\,0957+561 with over 95\% significance, whereas, we did not significantly detect FeK\(\alpha\) emission in B\,1422+231. We constructed differential microlensing light curves from absorption corrected count rates. We subsequently performed a microlensing analysis on the X-ray microlensing light curves to measure the X-ray source sizes in soft (0.83--3.6 keV), hard (3.6--21.8 keV), and full (0.83--21.8 keV) bands, based on either Bayesian or maximum likelihood probabilities. For B\,1422+231, sizes from the two methods are consistent with each other, e.g. \(R_X^{hard}/R_G = 6.17\pm5.48 \text{ (Bayesian), } 11.81\pm3.75 \text{ (maximum likelihood)}\), where \(R_G=GM_{BH}/c^2)\). However, for MG\,J0414+0534 and Q\,0957+561, the two methods yield completely different results suggesting that more frequently sampled data with better signal-to-noise ratio are needed to measure the source size for these two objects. Comparing the acquired size values with the radio-quiet sample in the literature we found that our results are consistent with X-ray source size scaling approximately as \(R_X \propto M_{BH}\) with the mass of the central supermassive black hole. Our results also indicate that radio-loud quasars tend to have larger unresolved X-ray emission sizes compared to the radio-quiet ones.
The objective of this study was to describe the distribution pattern of cerebellar hemispheric tentorial bridging (CHTB) veins on the tentorial surface in a case series of perimedian or paramedian ...supracerebellar approaches and to describe a novel technique to preserve these veins.
A series of 141 patients with various pathological processes in different locations was operated on via perimedian or paramedian supracerebellar approaches by the senior author from July 2006 through October 2022 and was retrospectively evaluated. During surgery, the number and locations of all CHTB veins were recorded to establish a distribution map on the tentorial surface, divided into nine zones. Patients were classified into four groups according to the surgical technique used to manage CHTB veins: 1) group 1 consisted of CHTB veins preserved without intervention during surgery or no CHTB veins found in the surgical route; 2) group 2 included CHTB veins coagulated during surgery; 3) group 3 included CHTB veins preserved with arachnoid and/or tentorial dissection from the cerebellar or tentorial surface, respectively; and 4) group 4 comprised CHTB veins preserved using a novel tentorial cut technique.
Overall, 141 patients were included in the study. Of these 141 patients, 38 were in group 1 (27%), 32 in group 2 (22.7%), 47 in group 3 (33.3%), and 24 in group 4 (17%). The total number of CHTB veins encountered was 207 during surgeries on one side. According to the distribution zones of the tentorium, zone 5 had the highest density of CHTB veins, while zone 7 had the lowest. Of the patients in group 4, 6 underwent the perimedian supracerebellar approach and 18 had the paramedian supracerebellar approach. There were 39 CHTB veins on the surface of the 24 cerebellar hemispheres in group 4. The tentorial cut technique was performed for 27 of 39 CHTB veins. Twelve veins were not addressed because they did not present any obstacles during approaches. During surgery, no complications were observed due to the tentorial cut technique.
Because there is no way to determine whether a CHTB vein can be sacrificed without complications, it is important to protect these veins in supracerebellar approaches. This new tentorial cut technique in perimedian or paramedian supracerebellar approaches makes it possible to preserve CHTB veins encountered during supracerebellar surgeries.
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