182 research outputs found
Survival of wild adults of Ceratitis capitata (Wiedemann) under natural winter conditions in north east Spain
The overwintering of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) at the northern limits of its geographic distribution is not yet well known. With the aim of estimating the survival rate of medfly adults in northeast Spain under natural winter conditions, a two-winter-season trial was carried out. A control was carried out in a climatic chamber at 25°C. The results showed that medfly adults were unable to survive the entire winter season in the Girona area. Climatic conditions, including the daily minimum temperature, daily maximum temperature and the high rainfall, appeared to be involved in adult mortality in winter
Dynamics in the satellite system of Triangulum: Is AndXXII a dwarf satellite of M33?
We present results from a spectroscopic survey of the dwarf spheroidal And
XXII and the two extended clusters EC1 and EC2. These three objects are
candidate satellites of the Triangulum galaxy, M33, which itself is likely a
satellite of M31. We use the DEep Imaging Multi-Object Spectrograph mounted on
the Keck-II telescope to derive radial velocities for candidate member stars of
these objects and thereby identify the stars that are most likely actual
members. Eleven most probable stellar members (of 13 candidates) are found for
AndXXII. We obtain an upper limit of sigma_v < 6.0 km s-1 for the velocity
dispersion of AndXXII, [Fe/H] ~ -1.6 for its metallicity, and 255pc for the
Plummer radius of its projected density profile. We construct a colour
magnitude diagram for AndXXII and identify both the red giant branch and the
horizontal branch. The position of the latter is used to derive a heliocentric
distance to And XXII of 853 pm 26 kpc. The combination of the radial velocity,
distance, and angular position of AndXXII indicates that it is a strong
candidate for being the first known satellite of M33 and one of the very few
examples of a galactic satellite of a satellite. N-body simulations imply that
this conclusion is unchanged even if M31 and M33 had a strong encounter in the
past few Gyr. We test the hypothesis that the extended clusters highlight
tidally stripped galaxies by searching for an excess cloud of halo-like stars
in their vicinity. We find such a cloud for the case of EC1 but not EC2. The
three objects imply a dynamical mass for M33 that is consistent with previous
estimates.Comment: 14 pages, 14 figures, revised for MNRAS publicatio
The scatter about the "Universal" dwarf spheroidal mass profile: A kinematic study of the M31 satellites, And V and And VI
While the satellites of the Milky Way (MW) have been shown to be largely
consistent in terms of their mass contained within one half--light radius
(M_{half}) with a "Universal" mass profile, a number of M31 satellites are
found to be inconsistent with such relations, and seem kinematically colder in
their central regions than their MW cousins. In this work, we present new
kinematic and updated structural properties for two M31 dSphs, And V and And VI
using data from the Keck Low Resolution Imaging Spectrograph (LRIS) and the
DEep Imaging Multi-Object Spectrograph (DEIMOS) instruments and the Subaru
Suprime-Cam imager. We measure systemic velocities of v_r=-393.1+/-4.2km/s and
-344.8+/-2.5km/s, and dispersions of sigma_v=11.5{+5.3}{-4.4}km/s and
sigma_v=9.4{+3.2}{-2.4}km/s for And V and And VI respectively, meaning these
two objects are consistent with the trends in sigma_v and r_{half} set by their
MW counterparts. We also investigate the nature of this scatter about the MW
dSph mass profiles for the "Classical" (i.e. M_V<-8) MW and M31 dSphs. When
comparing both the "classical" MW and M31 dSphs to the best--fit mass profiles
in the size--velocity dispersion plane, we find general scatter in both the
positive (i.e. hotter) and negative (i.e. colder) directions from these
profiles. However, barring one exception (CVnI) only the M31 dSphs are found to
scatter towards a colder regime, and, excepting the And I dSph, only MW objects
scatter to hotter dispersions. We also note that the scatter for the combined
population is greater than expected from measurement errors alone. We assess
this divide in the context of the differing disc-to-halo mass (i.e. stars and
baryons to total virial mass) ratios of the two hosts and argue that the
underlying mass profiles for dSphs differ from galaxy to galaxy, and are
modified by the baryonic component of the host.Comment: 15 pages, 8 figures. Small modifications made for referee report.
Accepted for publication in MNRAS (29/06/2011
VLT Observations of NGC 1097's "dog-leg" tidal stream
CONTEXT: Dwarf Spheroidal Galaxies and tidal streams. AIMS: We investigate
the structure and stellar population of two large stellar condensations (knots
A & B) along one of the faint optical "jet-like" tidal streams associated with
the spiral NGC 1097, with the goal of establishing their physical association
with the galaxy and their origin. METHODS: We use the VLT/FORS2 to get deep
V-band imaging and low-resolution optical spectra of two knots along NGC 1097's
northeast "dog-leg" tidal stream. With this data, we explore their morphology
and stellar populations. RESULTS: The FORS2 spectra show that the redshift of
knot A (and perhaps of knot B) is consistent with that of NGC 1097. The FORS2
photometry shows that the two knots match very well the photometric scaling
relations of canonical dwarf spheroidal galaxies (dSph). From the spectral
analysis we find that knot A is mainly composed of stars near G-type, with no
signs of ongoing star formation. Comparing its spectrum to a library of
Galactic GC spectra, we find that the stellar population of this dSph-like
object is most similar to intermediate to metal rich GCs. We find moreover,
that the tidal stream shows an "S" shaped inflection as well as a pronounced
stellar overdensity at knot A's position. This suggests that knot A is being
tidally stripped, and populates the stellar stream with its stars. CONCLUSIONS:
We have discovered that two knots along NGC 1097's northeast tidal stream share
most of their spectral and photometric properties with ordinary dwarf
spheroidal galaxies (dSph). Moreover, we find strong indications that the
"dog-leg" tidal stream arise from the tidal disruption of knot A. Since it has
been demonstrated that tidally stripping dSph galaxies need to loose most of
their dark matter before starting to loose stars, we suggest that knot A is at
present a CDM-poor object.Comment: 13 pages, 8 figures, accepted for publication in Astronomy &
Astrophysic
A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII
We present the first spectroscopic analysis of the faint M31 satellite
galaxies, AndXI and AndXIII, and a reanalysis of existing spectroscopic data
for two further faint companions, And IX and AndXII. By combining data obtained
using the DEIMOS spectrograph mounted on the Keck II telescope with deep
photometry from the Suprime-Cam instrument on Subaru, we have calculated global
properties for the dwarfs, such as systemic velocities, metallicites and
half-light radii.We find each dwarf to be very metal poor ([Fe/H] -2 both
photometrically and spectroscopically, from their stacked spectrum), and as
such, they continue to follow the luminosity-metallicity relationship
established with brighter dwarfs. We are unable to resolve a dispersion for And
XI due to small sample size and low S/N, but we set a one sigma upper limit of
sigma-v <5 km/s. For And IX, And XII and And XIII we resolve velocity
dispersions of v=4.5 (+3.4,-3.2), 2.6(+5.1,-2.6) and 9.7(+8.9,-4.5) km/s, and
derive masses within the half light radii of 6.2(+5.3,-5.1)x10^6 Msun, 2.4
(+6.5,-2.4)x10^6 Msun and 1.1(+1.4,-0.7)x10^7 Msun respectively. We discuss
each satellite in the context of the Mateo relations for dwarf spheroidal
galaxies, and the Universal halo profiles established for Milky Way dwarfs
(Walker et al. 2009). For both galaxies, this sees them fall below the
Universal halo profiles of Walker et al. (2009). When combined with the
findings of McConnachie & Irwin (2006a), which reveal that the M31 satellites
are twice as extended (in terms of both half-light and tidal radii) as their
Milky Way counterparts, these results suggest that the satellite population of
the Andromeda system could inhabit halos that are significantly different from
those of the Milky Way in terms of their central densities (abridged).Comment: 26 pages, 18 figures, MNRAS submitte
The masses of Local Group dwarf spheroidal galaxies: The death of the universal mass profile
We investigate the claim that all dwarf spheroidal galaxies (dSphs) reside
within halos that share a common, universal mass profile as has been derived
for dSphs of the Galaxy. By folding in kinematic information for 25 Andromeda
dSphs, more than doubling the previous sample size, we find that a singular
mass profile can not be found to fit all the observations well. Further, the
best-fit dark matter density profile measured for solely the Milky Way dSphs is
marginally discrepant (at just beyond the 1 sigma level) with that of the
Andromeda dSphs, where a profile with lower maximum circular velocity, and
hence mass, is preferred. The agreement is significantly better when three
extreme Andromeda outliers, And XIX, XXI and XXV, all of which have large
half-light radii (>600pc) and low velocity dispersions (sigma_v < 5km/s) are
omitted from the sample. We argue that the unusual properties of these outliers
are likely caused by tidal interactions with the host galaxy.Comment: ApJ in press, 16 pages, 7 figures. Updated to address referee
comment
A kinematic study of the Andromeda dwarf spheroidal system
We present a homogeneous kinematic analysis of red giant branch stars within
18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the
Keck I LRIS and Keck II DEIMOS spectrographs. Based on their g-i colors (taken
with the CFHT MegaCam imager), physical positions on the sky, and radial
velocities, we assign probabilities of dSph membership to each observed star.
Using this information, the velocity dispersions, central masses and central
densities of the dark matter halos are calculated for these objects, and
compared with the properties of the Milky Way dSph population. We also measure
the average metallicity ([Fe/H]) from the co-added spectra of member stars for
each M31 dSph and find that they are consistent with the trend of decreasing
[Fe/H] with luminosity observed in the Milky Way population. We find that three
of our studied M31 dSphs appear as significant outliers in terms of their
central velocity dispersion, And XIX, XXI and XXV, all of which have large
half-light radii (>700 pc) and low velocity dispersions (sigma_v<5 km/s). In
addition, And XXV has a mass-to-light ratio within its half-light radius of
just [M/L]_{half}=10.3^{+7.0}_{-6.7}, making it consistent with a simple
stellar system with no appreciable dark matter component within its 1 sigma
uncertainties. We suggest that the structure of the dark matter halos of these
outliers have been significantly altered by tides.Comment: 41 pages, 23 figures. Accepted for publication in Ap
Impact of IPDE-SQ personality disorders on the healthcare and societal costs of fibromyalgia patients: A cross-sectional study
Background: Data is lacking on comorbid personality disorders (PD) and fibromyalgia syndrome (FMS) in terms of prevalence, and associated healthcare and societal costs. The main aim of this study was to assess the prevalence of PD in FMS patients and to analyse whether the presence of comorbid PD is related to worse functional impairment and greater healthcare (medical visits, drug consumption, and medical tests) and societal costs. Methods: A cross-sectional study was performed using the baseline data of 216 FMS patients participating in a randomized, controlled trial carried out in three primary health care centres situated in the region of Barcelona, Spain. Measurement instruments included the International Personality Disorder Examination - Screening Questionnaire (IPDE-SQ), the Fibromyalgia Impact Questionnaire (FIQ), the Client Service Receipt Inventory (CSRI), and a socio-demographic questionnaire. Results: Most patients (65 %) had a potential PD according to the IPDE-SQ. The most prevalent PD were the avoidant (41.4 %), obsessive-compulsive (33.1 %), and borderline (27 %). We found statistically significant differences in functional impairment (FIQ scores) between FMS patients with potential PD vs non-PD (59.2 vs 51.1; p < 0.001). Multivariate regression analyses revealed that higher FIQ total scores and the presence of potential PD were related to more healthcare costs (primary and specialised care visits). Conclusions: As expected, PD are frequent comorbid conditions in patients with FMS. Our results suggest that the screening of comorbid PD in patients with FMS might be recommendable in order to detect potential frequent attenders to primary and specialised care
Forward and Back: Kinematics of the Palomar 5 Tidal Tails
The tidal tails of Palomar 5 (Pal 5) have been the focus of many
spectroscopic studies in an attempt to identify individual stars lying along
the stream and characterise their kinematics. The well-studied trailing tail
has been explored out to a distance of 15^\text{o} from the cluster centre,
while less than four degrees have been examined along the leading tail. In this
paper, we present results of a spectroscopic study of two fields along the
leading tail that we have observed with the AAOmega spectrograph on the
Anglo-Australian telescope. One of these fields lies roughly 7^\text{o} along
the leading tail, beyond what has been previously been explored
spectroscopically. Combining our measurements of kinematics and line strengths
with Pan-STARRS1 photometric data and Gaia EDR3 astrometry, we adopt a
probabilistic approach to identify 16 stars with high probability of belonging
to the Pal 5 stream. Eight of these stars lie in the outermost field and their
sky positions confirm the presence of ``fanning'' in the leading arm. We also
revisit previously-published radial velocity studies and incorporate Gaia EDR3
astrometry to remove interloping field stars. With a final sample of 109 {\it
bona fide} Pal 5 cluster and tidal stream stars, we characterise the 3D
kinematics along the the full extent of the system. We provide this catalogue
for future modeling work.Comment: 13 pages, 8 figures, accepted for publication in MNRAS. The extended
version of Table 4 is available as an ancillery file, and will be
supplementary material in MNRA
Kinematics of Stars in Kapteyn Selected Area 71: Sampling the Monoceros and Sagittarius Tidal Streams
We present a 3D kinematical analysis of stars located in Kapteyn Selected
Area 71 (l = 167.1, b = -34.7), where previously a stellar excess was found
(Dinescu et al. 2002, Newberg et al. 2002). Previous findings indicated that
the stellar excess has a cold kinematical signature as inferred from proper
motions, and was initially associated with debris from the Sagittarius dwarf
galaxy (Sgr) -- namely the southern trailing tail. We have obtained radial
velocities using the Hydra multiobject spectrograph on the WIYN 3.5 m
telescope. Results for 183 proper-motion selected stars indicate that the
dominant population in this stellar excess is not debris from Sgr, but rather a
population that kinematically belongs to the ring-like stream that is now known
as the Monoceros stream. The orbit determined for this population agrees very
well with the predictions for the Monoceros stream from Penarrubia et al.
(2005). The radial-velocity dispersion of this population is between 20 and 30
km/s, lower than that of the Galactic field. Also, the shape of the
radial-velocity distribution shows a sharp cut-off on one side, which is more
in line with model predictions of the disruption of a satellite rather than
with the distribution of the Galactic field. Despite the fact that we now
believe most of the stars in the stellar excess to be part of Monoceros, about
ten stars in this stellar excess have highly negative radial velocities, which
is a clear indication of their membership to the Sgr trailing tidal tail.Comment: Accepted for publication in the Astronomical Journal - 26 pages, 8
figures, (Figures 7 and 8 in lower resolution
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