B and V time-series photometry of the M31 dwarf spheroidal satellite Andromeda XXI (And XXI) was obtained with the Large Binocular Cameras at the Large Binocular Telescope. We have identified 50 ...variables in And XXI, of which 41 are RR Lyrae stars (37 fundamental-mode-RRab, and 4 first-overtone-RRc, pulsators) and 9 are Anomalous Cepheids (ACs). The average period of the RRab stars (left angle bracketP sub(ab)right angle bracket = 0.64 days) and the period-amplitude diagram place And XXI in the class of Oosterhoff II-Oosterhoff-Intermediate objects. From the average luminosity of the RR Lyrae stars we derived the galaxy distance modulus of (m - M) sub(0) = 24.40 + or - 0.17 mag, which is smaller than previous literature estimates, although still consistent with them within 1sigma. The galaxy color-magnitude diagram shows evidence for the presence of three different stellar generations in And XXI: (1) an old (~12 Gyr) and metal-poor (Fe/H = -1.7 dex) component traced by the RR Lyrae stars; (2) a slightly younger (10-6 Gyr) and more metal-rich (Fe/H = -1.5 dex) component populating the red horizontal branch, and (3) an intermediate age (~1 Gyr) component with the same metallicity that produced the ACs. Finally, we provide hints that And XXI could be the result of a minor merging event between two dwarf galaxies.
In our first paper, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses, M{sub BH}, ...imaged at 3.6 μm with Spitzer. Our sample is the largest to date and, for the first time, the decompositions were checked for consistency with the galaxy kinematics. We present correlations between M{sub BH} and the host spheroid (and galaxy) luminosity, L{sub sph} (and L{sub gal}), and also stellar mass, M{sub ∗,sph}. While most previous studies have used galaxy samples that were overwhelmingly dominated by high-mass, early-type galaxies, our sample includes 17 spiral galaxies, half of which have M{sub BH}<10{sup 7} M{sub ⊙}, and allows us to better investigate the poorly studied low-mass end of the M{sub BH}--M{sub ∗,sph} correlation. The bulges of early-type galaxies follow M{sub BH} ∝ M{sub ∗,sph}{sup 1.04±0.10} and define a tight red sequence with intrinsic scatter ϵ{sub (M{sub B{sub H|M{sub ∗{sub ,{sub s{sub p{sub h)}}} = 0.43 ± 0.06 dex and a median M{sub BH}/M{sub ∗,sph} ratio of 0.68 ± 0.04%, i.e., a ±2σ range of 0.1%–5%. At the low-mass end, the bulges of late-type galaxies define a much steeper blue sequence, with M{sub BH} ∝ M{sub ∗,sph}{sup 2−3} and M{sub BH}/M{sub ∗,sph} equal to 0.02% at M{sub BH} ≈ 10{sup 6} M{sub ⊙}. We additionally report that (1) our Sérsic galaxy sample follows M{sub BH} ∝ M{sub ∗,sph}{sup 1.48±0.20}, a less steep sequence than previously reported; (2) bulges with Sérsic index n{sub sph}<2, argued by some to be pseudo-bulges, are not offset to lower M{sub BH} from the correlation defined by the current bulge sample with n{sub sph}>2; and (3) L{sub sph} and L{sub gal} correlate equally well with M{sub BH}, in terms of intrinsic scatter, only for early-type galaxies—once reasonable numbers of spiral galaxies are included, the correlation with L{sub sph} is better than that with L{sub gal}.
In our first paper, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses, MBH, imaged at ...$3.6\; \mu {\rm{m}}$ with Spitzer. Our sample is the largest to date and, for the first time, the decompositions were checked for consistency with the galaxy kinematics. We present correlations between MBH and the host spheroid (and galaxy) luminosity, Lsph (and Lgal), and also stellar mass, ${M}_{*,\mathrm{sph}}.$ We additionally report that (1) our Sersic galaxy sample follows ${M}_{\mathrm{BH}}\; \propto \; {M}_{*,\mathrm{sph}} super({1.48\pm 0.20}),$ a less steep sequence than previously reported; (2) bulges with Sersic index ${n}_{\mathrm{sph}}\lt 2,$ argued by some to be pseudo-bulges, are not offset to lower MBH from the correlation defined by the current bulge sample with ${n}_{\mathrm{sph}}\gt 2; $ and (3) Lsph and Lgal correlate equally well with MBH, in terms of intrinsic scatter, only for early-type galaxies-once reasonable numbers of spiral galaxies are included, the correlation with Lsph is better than that with Lgal.
ABSTRACT
In our first paper, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses,
M
BH
, ...imaged at
with
Spitzer
. Our sample is the largest to date and, for the first time, the decompositions were checked for consistency with the galaxy kinematics. We present correlations between
M
BH
and the host spheroid (and galaxy) luminosity,
L
sph
(and
L
gal
), and also stellar mass,
While most previous studies have used galaxy samples that were overwhelmingly dominated by high-mass, early-type galaxies, our sample includes 17 spiral galaxies, half of which have
and allows us to better investigate the poorly studied low-mass end of the
correlation. The bulges of early-type galaxies follow
and define a tight
red
sequence
with intrinsic scatter
and a median
ratio of 0.68 ± 0.04%, i.e., a
range of 0.1%–5%. At the low-mass end, the bulges of late-type galaxies define a much steeper
blue
sequence
, with
and
equal to
at
We additionally report that (1) our Sérsic galaxy sample follows
a less steep sequence than previously reported; (2) bulges with Sérsic index
argued by some to be pseudo-bulges, are not offset to lower
M
BH
from the correlation defined by the current bulge sample with
and (3)
L
sph
and
L
gal
correlate equally well with
M
BH
, in terms of intrinsic scatter, only for early-type galaxies—once reasonable numbers of spiral galaxies are included, the correlation with
L
sph
is better than that with
L
gal
.
ABSTRACT
Galaxy clusters are key places to study the contribution of nature (i.e. mass and morphology) and nurture (i.e. environment) in the formation and evolution of galaxies. Recently, a number of ...clusters at z > 1, i.e. corresponding to the first epochs of the cluster formation, have been discovered and confirmed spectroscopically. We present new observations obtained with the LBT Near Infrared Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER) spectrograph at Large Binocular Telescope (LBT) of a sample of star‐forming galaxies associated with a large‐scale structure around the radio galaxy 7C 1756+6520 at z = 1.42. Combining our spectroscopic data and the literature photometric data, we derived some of the properties of these galaxies: star formation rate, metallicity and stellar mass. With the aim of analysing the effect of the cluster environment on galaxy evolution, we have located the galaxies in the plane of the so‐called fundamental metallicity relation (FMR), which is known not to evolve with redshift up to z = 2.5 for field galaxies, but it is still unexplored in rich environments at low and high redshifts. We found that the properties of the galaxies in the cluster 7C 1756+6520 are compatible with the FMR which suggests that the effect of the environment on galaxy metallicity at this early epoch of cluster formation is marginal. As a side study, we also report the spectroscopic analysis of a bright active galactic nucleus, belonging to the cluster, which shows a significant outflow of gas.
Galaxy clusters are key places to study the contribution of nature (i.e. mass and morphology) and nurture (i.e. environment) in the formation and evolution of galaxies. Recently, a number of clusters ...at z > 1, i.e. corresponding to the first epochs of the cluster formation, have been discovered and confirmed spectroscopically. We present new observations obtained with the LBT Near Infrared Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER) spectrograph at Large Binocular Telescope (LBT) of a sample of star-forming galaxies associated with a large-scale structure around the radio galaxy 7C 1756+6520 at z = 1.42. Combining our spectroscopic data and the literature photometric data, we derived some of the properties of these galaxies: star formation rate, metallicity and stellar mass. With the aim of analysing the effect of the cluster environment on galaxy evolution, we have located the galaxies in the plane of the so-called fundamental metallicity relation (FMR), which is known not to evolve with redshift up to z = 2.5 for field galaxies, but it is still unexplored in rich environments at low and high redshifts. We found that the properties of the galaxies in the cluster 7C 1756+6520 are compatible with the FMR which suggests that the effect of the environment on galaxy metallicity at this early epoch of cluster formation is marginal. As a side study, we also report the spectroscopic analysis of a bright active galactic nucleus, belonging to the cluster, which shows a significant outflow of gas.
Background
Computed tomographic perfusion (CTp) imaging is a promising technique that allows functional imaging, as an adjunct to a morphologic CT examination, that can be used as an aid to carefully ...evaluate the response to therapy in oncologic patients. Considering this statement, it could be desirable that the measurements obtained with the CT perfusion software, and their upgrades, are consistent and reproducible.
Purpose
To determine how commercial software upgrades impact on algorithm consistency and stability among the three version upgrades of the same platform in a preliminary study.
Material and Methods
Blood volume (BV), blood flow (BF), mean transit time (MTT), and permeability surface area product (PS) were calculated with repeated measurements (n = 1119) while truncating the time density curve at different time values in six CT perfusion studies using CT perfusion software version 4D (CT Perfusion 4D), then repeated with the previous version (CT Perfusion 3.0 and CT Perfusion 4.0), using a fixed ROI both for arterial input and target lesion. The software upgrades were compared in pairs by applying a Kolmogorov-Smirnov test to all the parameters measured. Stability and reliability of the three versions were verified through the variation of the truncated parameters.
Results
The three software versions provided different parent distributions for approximately 80% of the 72 parameters measured. A complete agreement was found only for one patient in version 3.0 vs. 4.0 and 3.0 vs. 4D. Perfusion 4.0 vs. 4D: a complete agreement was found only in two cases. Parameters obtained with Perfusion 4D always showed the lowest standard deviation in all temporal intervals and also for all individual parameters.
Conclusion
The three versions of the same platform tested yield different perfusion measurements. Thus, our preliminary results show that Perfusion 4D version uses a stable deconvolution algorithm to provide more reliable measurements.
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