Groups of Galaxies in AEGIS: The 200 ksec Chandra Extended X-ray Source catalogue

We present the discovery of seven X-ray emitting groups of galaxies selected as extended X-ray sources in the 200 ksec Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). In addition, we report on AGN activity associated to these systems. Using the DEEP2 Galaxy Redshift Survey coverage, we identify optical counterparts and determine velocity dispersions. In particular, we find three massive high-redshift groups at z>0.7, one of which is at z=1.13, the first X-ray detections of spectroscopically selected DEEP2 groups. We also present a first look at the the L_X-T, L_X-sigma, and sigma-T scaling relations for high-redshift massive groups. We find that the properties of these X-ray selected systems agree well with the scaling relations of similar systems at low redshift, although there are X-ray undetected groups in the DEEP2 catalogue with similar velocity dispersions. The other three X-ray groups with identified redshifts are associated with lower mass groups at z~0.07 and together form part of a large structure or "supergroup" in the southern portion of the AEGIS field. All of the low-redshift systems are centred on massive elliptical galaxies, and all of the high-redshift groups have likely central galaxies or galaxy pairs. All of the central group galaxies host X-ray point sources, radio sources, and/or show optical AGN emission. Particularly interesting examples of central AGN activity include a bent-double radio source plus X-ray point source at the center of a group at z=0.74, extended radio and double X-ray point sources associated to the central galaxy in the lowest-redshift group at z=0.066, and a bright green valley galaxy (part of a pair) in the z=1.13 group which shows optical AGN emission lines.Comment: accepted to MNRAS, 15 pages, 11 figures, for version with full resolution figures see http://www.ucolick.org/~tesla/aegis_groups.ps.g

Obscured Starburst Activity in High Redshift Clusters and Groups

Using Spitzer-MIPS 24um imaging and Keck spectroscopy we examine the nature of the obscured star forming population in three clusters and three groups at z~0.9. These six systems are components of the Cl1604 supercluster, the largest structure imaged by Spitzer at redshifts near unity. We find that the average density of 24um-detected galaxies within the Cl1604 clusters is nearly twice that of the surrounding field and that this overdensity scales with the cluster's dynamical state. The 24um-bright members often appear optically unremarkable and exhibit only moderate [OII] line emission due to severe obscuration. Their spatial distribution suggests they are an infalling population, but an examination of their spectral properties, morphologies and optical colors indicate they are not simply analogs of the field population that have yet to be quenched. Using stacked composite spectra, we find the 24um-detected cluster and group galaxies exhibit elevated levels of Balmer absorption compared to galaxies undergoing normal, continuous star formation. A similar excess is not observed in field galaxies with equivalent infrared luminosities, indicating a greater fraction of the detected cluster and group members have experienced a burst of star formation in the recent past compared to their counterparts in the field. Our results suggest that gas-rich galaxies at high redshift experience a temporary increase in their star formation activity as they assemble into denser environments. Using HST-ACS imaging we find that disturbed morphologies are common among the 24um-detected cluster and group members and become more prevalent in regions of higher galaxy density. We conclude that mergers are the dominant triggering mechanism responsible for the enhanced star formation found in the Cl1604 groups, while a mix of harassment and mergers are likely driving the activity of the cluster galaxies.Comment: 18 pages, 19 figures, submitted to Ap

Hα star formation main sequence in cluster and field galaxies at z ∼ 1.6

We calculate Hα-based star formation rates and determine the star formation rate–stellar mass relation for members of three Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) clusters at z ∼ 1.6 and serendipitously identified field galaxies at similar redshifts to the clusters. We find similar star formation rates in cluster and field galaxies throughout our range of stellar masses. The results are comparable to those seen in other clusters at similar redshifts, and consistent with our previous photometric evidence for little quenching activity in clusters. One possible explanation for our results is that galaxies in our z ∼ 1.6 clusters have been accreted too recently to show signs of environmental quenching. It is also possible that the clusters are not yet dynamically mature enough to produce important environmental quenching effects shown to be important at low redshift, such as ram-pressure stripping or harassment

The DEEP2 Galaxy Redshift Survey: Environments of Poststarburst Galaxies at z~0.1 and z~0.8

Postststarburst (K+A) galaxies are candidates for galaxies in transition from a star-forming phase to a passively-evolving phase. We have spectroscopically identified large samples of K+A galaxies both in the SDSS at z~0.1 and in the DEEP2 survey at z~0.8, using a robust selection method based on a cut in Hbeta emission rather than the more problematic [OII] 3727. Based on measurements of the overdensity of galaxies around each object, we find that K+A galaxies brighter than 0.4L*_B at low-z have a similar, statistically indistinguishable environment distribution as blue galaxies, preferring underdense environments, but dramatically different from that of red galaxies. However, at higher-z, the environment distribution of K+A galaxies is more similar to red galaxies than to blue galaxies. We conclude that the quenching of star formation and the build-up of the red sequence through the K+A phase is happening in relatively overdense environments at z~1 but in relatively underdense environments at z~0. Although the relative environments where quenching occurs are decreasing with time, the corresponding absolute environment may have stayed the same along with the quenching mechanisms, because the mean absolute environments of all galaxies has to grow with time. In addition, we do not find any significant dependence on luminosity in the environment distribution of K+As. The existence of a large K+A population in the field at both redshifts indicates that cluster-specific mechanisms cannot be the dominant route by which these galaxies are formed. We also demonstrates that studying K+A-environment relations by measuring the K+A fraction in different environments is highly non-robust. Statistical comparisons of the overall environment distributions of different populations are much better behaved.Comment: 21 pages, 13 figures, 4 tables, submitted to MNRAS; v2: major revision in Sec 5, 6, 7, and 9. Implemented robust statistical techniques in place of K+A fraction measurements; conclusions on the environment distribution of poststarbursts at z~0.8 have changed. Completely new discussion added. v3: minor changes matching the accepted versio

Public preferences for vaccination campaigns in the COVID-19 endemic phase:insights from the VaxPref database

Objective: Despite widespread perceptions that SARS-CoV-2 (COVID-19) is no longer a significant threat, the virus continues to loom, and new variants may require renewed efforts to control its spread. Understanding how individual preferences and attitudes influence vaccination behaviour and policy compliance in light of the endemic phase is crucial in preparation for this scenario. Method: This paper presents descriptive data from a global stated choice survey conducted in 22 countries across 6 different continents between July 2022 and August 2023, and reports the methodological work developed to address the need for comparable data. Results: This study included 50,242 respondents. Findings indicated significant heterogeneity across countries in terms of vaccination status and willingness to accept boosters. Vaccine hesitancy and refusal were driven by lower trust in public health bodies, younger age, and lower educational levels. Refusers and hesitant people reported lower willingness to take risks compared to those fully vaccinated (p&lt;0.05). Lower mental health levels were found for the hesitant cohort (p&lt;0.05). Conclusions: Insights from this database can help public health authorities to gain a new understanding of the vaccine hesitancy phenomenon, support them in managing the transition from the pandemic to the endemic phase, and favour a new stream of research to maximise behavioural response to vaccination programs in preparation of future pandemics.</p

Public preferences for vaccination campaigns in the COVID-19 endemic phase:insights from the VaxPref database

Objective: Despite widespread perceptions that SARS-CoV-2 (COVID-19) is no longer a significant threat, the virus continues to loom, and new variants may require renewed efforts to control its spread. Understanding how individual preferences and attitudes influence vaccination behaviour and policy compliance in light of the endemic phase is crucial in preparation for this scenario. Method: This paper presents descriptive data from a global stated choice survey conducted in 22 countries across 6 different continents between July 2022 and August 2023, and reports the methodological work developed to address the need for comparable data. Results: This study included 50,242 respondents. Findings indicated significant heterogeneity across countries in terms of vaccination status and willingness to accept boosters. Vaccine hesitancy and refusal were driven by lower trust in public health bodies, younger age, and lower educational levels. Refusers and hesitant people reported lower willingness to take risks compared to those fully vaccinated (p&lt;0.05). Lower mental health levels were found for the hesitant cohort (p&lt;0.05). Conclusions: Insights from this database can help public health authorities to gain a new understanding of the vaccine hesitancy phenomenon, support them in managing the transition from the pandemic to the endemic phase, and favour a new stream of research to maximise behavioural response to vaccination programs in preparation of future pandemics.</p

Public preferences for vaccination campaigns in the COVID-19 endemic phase: insights from the VaxPref database

Objective Despite widespread perceptions that SARS-CoV-2 (COVID-19) is no longer a significant threat, the virus continues to loom, and new variants may require renewed efforts to control its spread. Understanding how individual preferences and attitudes influence vaccination behaviour and policy compliance in light of the endemic phase is crucial in preparation for this scenario. Method This paper presents descriptive data from a global stated choice survey conducted in 22 countries across 6 different continents between July 2022 and August 2023, and reports the methodological work developed to address the need for comparable data. Results This study included 50,242 respondents. Findings indicated significant heterogeneity across countries in terms of vaccination status and willingness to accept boosters. Vaccine hesitancy and refusal were driven by lower trust in public health bodies, younger age, and lower educational levels. Refusers and hesitant people reported lower willingness to take risks compared to those fully vaccinated (p<0.05). Lower mental health levels were found for the hesitant cohort (p<0.05). Conclusions Insights from this database can help public health authorities to gain a new understanding of the vaccine hesitancy phenomenon, support them in managing the transition from the pandemic to the endemic phase, and favour a new stream of research to maximise behavioural response to vaccination programs in preparation of future pandemics

COVID-19 Vaccination of Individuals with Down Syndrome—Data from the Trisomy 21 Research Society Survey on Safety, Efficacy, and Factors Associated with the Decision to Be Vaccinated

Individuals with Down syndrome (DS) are among the groups with the highest risk for severe COVID-19. Better understanding of the efficacy and risks of COVID-19 vaccines for individuals with DS may help improve uptake of vaccination. The T21RS COVID-19 Initiative launched an international survey to obtain information on safety and efficacy of COVID-19 vaccines for individuals with DS. De-identified survey data collected between March and December 2021 were analyzed. Of 2172 individuals with DS, 1973 (91%) had received at least one vaccine dose (57% BNT162b2), 107 (5%) were unvaccinated by choice, and 92 (4%) were unvaccinated for other reasons. Most participants had either no side effects (54%) or mild ones such as pain at the injection site (29%), fatigue (12%), and fever (7%). Severe side effects occurred in <0.5% of participants. About 1% of the vaccinated individuals with DS contracted COVID-19 after vaccination, and all recovered. Individuals with DS who were unvaccinated by choice were more likely to be younger, previously recovered from COVID-19, and also unvaccinated against other recommended vaccines. COVID-19 vaccines have been shown to be safe for individuals with DS and effective in terms of resulting in minimal breakthrough infections and milder disease outcomes among fully vaccinated individuals with DS

COVID-19 Vaccination of Individuals with Down Syndrome—Data from the Trisomy 21 Research Society Survey on Safety, Efficacy, and Factors Associated with the Decision to Be Vaccinated

Individuals with Down syndrome (DS) are among the groups with the highest risk for severe COVID-19. Better understanding of the efficacy and risks of COVID-19 vaccines for individuals with DS may help improve uptake of vaccination. The T21RS COVID-19 Initiative launched an international survey to obtain information on safety and efficacy of COVID-19 vaccines for individuals with DS. De-identified survey data collected between March and December 2021 were analyzed. Of 2172 individuals with DS, 1973 (91%) had received at least one vaccine dose (57% BNT162b2), 107 (5%) were unvaccinated by choice, and 92 (4%) were unvaccinated for other reasons. Most participants had either no side effects (54%) or mild ones such as pain at the injection site (29%), fatigue (12%), and fever (7%). Severe side effects occurred in <0.5% of participants. About 1% of the vaccinated individuals with DS contracted COVID-19 after vaccination, and all recovered. Individuals with DS who were unvaccinated by choice were more likely to be younger, previously recovered from COVID-19, and also unvaccinated against other recommended vaccines. COVID-19 vaccines have been shown to be safe for individuals with DS and effective in terms of resulting in minimal breakthrough infections and milder disease outcomes among fully vaccinated individuals with DS