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The X-ray bright bubbles at the Galactic Centre provide an opportunity to understand the effects of feedback on galaxy evolution. The shells of the eROSITA bubbles show enhanced X-ray emission over the sky background. Previously, these shells were assumed to have a single temperature component and to trace the shock-heated lower-temperature halo gas. Using Suzaku observations, we show that the X-ray emission of the shells is more complex and best described by a two-temperature thermal model: one component close to the Galaxy’s virial temperature and the other at supervirial temperatures. Furthermore, we demonstrate that temperatures of the virial and supervirial components are similar in the shells and in the ambient medium, although the emission measures are significantly higher in the shells. This leads us to conclude that the eROSITA bubble shells are X-ray bright because they trace denser gas, not because they are hotter. Given that the pre- and postshock temperatures are similar and the compression ratio of the shock is high, we rule out that the bubble shells trace adiabatic shocks, in contrast to what was assumed in previous studies. We also observe non-solar Ne/O and Mg/O ratios in the shells, favouring stellar feedback models for the formation of the bubbles and settling a long-standing debate on their origin.The eROSITA bubbles and their surrounding regions are best described by the same two-temperature model, implying that the shells are bright because they are denser, not hotter. Also reported are non-solar Mg/O and Ne/O ratios, which support the stellar-feedback origin of the bubbles.

Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be hidden in a web of warm-hot intergalactic medium. This matter was shock-heated during the collapse of density perturbations that led to the formation of the relaxed structures that we see today. Finding the missing baryons and thereby producing a complete inventory of possibly the only detectable component of the energy-mass budget of the universe is crucial to validate or invalidate our standard cosmological model.

On the trail of the missing baryons According to current cosmological models, baryons — elementary particles found in normal everyday matter — make up about 5% of the total mass density of the Universe. Observations at high redshifts support that prediction, but nearer home in space and time only half as many baryons have been detected. This has prompted a search for missing ‘normal’ (as opposed to ‘dark’) matter. Nicastro et al . report the discovery of a previously unknown source of baryons lying in a warm–hot phase of the intergalactic medium — and their mass is consistent with that of the ‘missing’ baryons Recent cosmological measurements indicate that baryons comprise about four per cent of the total mass-energy density of the Universe 1 , 2 , which is in accord with the predictions arising from studies of the production of the lightest elements 3 . It is also in agreement with the actual number of baryons detected at early times (redshifts z > 2) 4 , 5 . Close to our own epoch ( z < 2), however, the number of baryons detected add up to just over half (∼ 55 per cent) of the number seen at z > 2 (refs 6–11 ), meaning that about ∼45 per cent are ‘missing’. Here we report a determination of the mass-density of a previously undetected population of baryons, in the warm–hot phase of the intergalactic medium. We show that this mass density is consistent, within the uncertainties, with the mass density of the missing baryons.

High-redshift AGN holds the key to understanding early structure formation and to probe the Universe during its infancy. We review the latest searches for high-z AGN in the deepest X-ray field so far, the Chandra Deep Field South (CDFS) 4 Msecond exposure. We do not confirm the positive detection of a signal in the stacked Chandra images at the position of z~6 galaxies recently reported by Treister and collaborators (2011). We present z>3 X-ray sources number counts in the 0.5–2 keV band, obtained joining CDFS faint detections (see Fiore et al. (2011)), with Chandra-COSMOS and XMM-COSMOS detections. We use these number counts to make predictions for surveys with three mission concepts: Athena, WFXT, and a Super-Chandra.

The authors explore gender differences in the play of children of migrant farm workers from Mexico. They review the literature that indicates children exhibit gender differences in their play as early as three years old, but the authors claim their findings do not corroborate the existing research on gender differences in play. The twenty-one migrant girls and twenty boys they studied failed to exhibit gender differences in their play in the classroom, during their free play outdoors, or during their unstructured play at home. The authors also found no gender differences among these children in cognitive tasks, social interactions, and their use of their preferred language. The authors offer several reasons for these results and note that research studies of other cultural groups suggest that gender roles are altered when communities are displaced or undergo migration. The authors speculate on the possible implications of their findings for preschool teaching.

Teacher education faculty developed an innovative immersion-based professional development initiative termed High Impact Immersion Experience (H.I.I.E.) to address the problem of novice preservice teachers' lack of experience working in high-poverty schools with significant cultural diversity. A qualitative action research approach was designed to explore perceptions of the preservice teachers related to H.I.I.E. Immersing novice preservice teachers in high-needs elementary classrooms early in their education programs was hypothesized to provide academically challenging learning opportunities and build strong professional relationships in schools. Aligned with the High Impact Educational Practices described by George Kuhn (2008), faculty developed an early immersion experience for a cohort of 20 novice preservice teachers; 19 participated in the study. The preservice teachers were placed in 5 local elementary schools for 5 full consecutive weeks and were mentored by cooperating teachers, university faculty, and other school personnel. Findings suggested that immersion offers preservice teachers an opportunity to be involved in a broad range of activities in the classroom; have a variety of interactions with school staff, build deeper relationships; and develop metacognitive skills that lead to personal transformation and prepare them to work in high-needs schools. Implications of this study indicate that successful immersion experiences, such as H.I.I.E., should be an integral part of preparing teachers.

A comparison of pseudobulges in S0 and spiral galaxies is presented using structural parameters derived from 2-d decomposition of mid-infrared images taken at 3.6 μm by Spitzer IRAC. The position of the bulges on the Kormendy diagram has been used as an initial classification criterion for determining the nature of the bulge. To make the classification more secure, the criterion proposed by Fisher and Drory (2008) has also been used, which involves using the n = 2 division line on Sérsic index. We find that among the 185 S0 galaxies, 27 are pseudobulge hosts while 160 are classical. Of these 25 pseudobulge hosts, only two belong to the bright luminosity class (MK < 22.66, AB system) while rest belong to the faint luminosity class (MK > 22.66, AB system). We find that among spiral galaxies, 77 % (24 of 31) of the bulges are classified as pseudobulges. As pointed out by various studies, the presence of such a large fraction poses problems to our current picture of galaxy formation. How ever, our primary result is that the disk scale length of pseudobulge hosting S0s is significantly smaller on average than that of their spiral counterparts. This can be explained as a lowered disk luminosity which in turn implies that S0s have evolved from spiral progenitors. We also argue that early type spirals are more likely to be the progenitors based on bulge and total luminosity arguments. We speculate that if late type spirals hosting pseudobulges have to evolve into S0s, an additional mechanism along with gas stripping of spirals is needed. We have also investigated the effect of environment on pseudobulges in the two samples, but no significant trends were found in the properties of the pseudobulges as a function of the various structural parameters. The study is made more difficult because of the low number statistics one deals with when the sample is sub-divided based on whether it is in a field or group/cluster environment. The study of pseudobulges based on environment, however, is an interesting one and is something that can be considered for the future by carefully selecting a sample with statistically meaningful number of objects from diverse environments.

The number of baryons detected in the low-redshift ( z < 1) Universe is far smaller than the number detected in corresponding volumes at higher redshifts. Simulations 1 , 2 , 3 of the formation of structure in the Universe show that up to two-thirds of the ‘missing’ baryons may have escaped detection because of their high temperature and low density. One of the few ways to detect this matter directly is to look for its signature in the form of ultraviolet absorption lines in the spectra of background sources such as quasars. Here we show that the amplitude of the average velocity vector of ‘high velocity’ O  vi (O 5+ ) absorption clouds detected in a survey 4 of ultraviolet emission from active galactic nuclei decreases significantly when the vector is transformed to the frames of the Galactic Standard of Rest and the Local Group of galaxies. At least 82 per cent of these absorbers are not associated with any ‘high velocity’ atomic hydrogen complex in our Galaxy, and are therefore likely to result from a primordial warm–hot intergalactic medium pervading an extended corona around the Milky Way or the Local Group. The total mass of baryons in this medium is estimated to be up to ∼10 12 solar masses, which is of the order of the mass required 5 to dynamically stabilize the Local Group.

We report on the measurement of the thermal Sunyaev-Zel'dovich (tSZ) Effect in the circumgalactic medium (CGM) of 641,923 galaxies with \\(\\rm M_\\star\\)=\\(\\rm 10^{9.8-11.3}M_\\odot\\) at \\(z<\\)0.5, pushing the exploration of tSZ Effect to lower-mass galaxies compared to previous studies. We cross-correlate the galaxy catalog of \\(WISE\\) and \\(SuperCosmos\\) with the Compton-\\(y\\) maps derived from the combined data of \\(Atacama\\) \\(Cosmology\\) \\(Telescope\\) and \\(Planck\\). We improve on the data analysis methods (correcting for cosmic infrared background and Galactic dust, masking galaxy clusters and radio sources, stacking, aperture photometry), as well as modeling (taking into account beam smearing, \"two-halo\" term, zero-point offset). We have constrained the thermal pressure in the CGM of \\(\\rm M_\\star\\)=\\(\\rm 10^{10.6-11.3}M_\\odot\\) galaxies for a generalized NFW profile and provided upper limits for \\(\\rm M_\\star\\)=\\(\\rm 10^{9.8-10.6}M_\\odot\\) galaxies. The relation between \\(\\rm M_{500}\\) (obtained from an empirical \\(\\rm M_\\star\\)-\\(\\rm M_{200}\\) relation and a concentration factor) and \\(\\rm \\tilde Y^{sph}_{R500}\\) (a measure of the thermal energy within R\\(_{500}\\)) is \\(>\\)2\\(\\sigma\\) steeper than the self-similarity and the deviation from the same that has been reported previously in higher mass halos. We calculate the baryon fraction of the galaxies, \\(f_b\\), assuming the CGM to be at the virial temperature that is derived from \\(\\rm M_{200}\\). \\(f_b\\) exhibits a non-monotonic trend with mass, with \\(\\rm M_\\star\\)=\\(\\rm 10^{10.9-11.2}M_\\odot\\) galaxies being baryon sufficient.