X-Ray IGM in the Local Group

Recent observations with the dispersive X-ray spectrometers aboard Chandra and Newton Observatory have begun to probe the properties of the X-ray intergalactic medium (IGM) at small redshifts. Using large quantities (~950 ksec) of spectroscopic data acquired using the RGS aboard Newton Observatory, we investigated the intervening material toward three low redshift, high Galactic latitude AGNs with nominally featureless spectra: Mrk421, PKS2155-304 and 3C273. Each spectrum provides clear evidence for what appears to be a local (z~0), highly ionized absorbing medium betrayed by the OVII 1s-2p resonance transition feature seen at 21.6A (N[OVII] ~ 1E16 cm-2). Measurements are also made for the Lyman alpha transition of the adjacent ionization state, (OVIII; 18.97A), which potentially constrains the absorber's temperature. Finally, in a collisional equilibrium approximation, upper limits to diffuse emission intensities place upper limits on the electron density (ne < 2E-4 cm-3), lower limits on the scale length of the absorber (L > 140 kpc) and lower limits on its mass (M > 5E10 M[sun]). Limits on the absorber's scale length and its velocity distribution lead us to identify it with the Local Group.Comment: 6 pages, 1 table and 2 figs. Latex. To appear in "The IGM/Galaxy Connection: The Distribution of Baryons at z=0" to be published by Kluwer Academic Publishing. Resubmitted with 2 typos corrected, page 5 and figure 2. Thanks to Masao Sako for pointing these ou

IceCube Neutrinos from Hadronically Powered Gamma-Ray Galaxies

In this work we use a multi-messenger approach to determine if the high energy diffuse neutrino flux observed by the IceCube Observatory can originate from $\gamma$-ray sources powered by Cosmic Rays interactions with gas. Typical representatives of such sources are Starburst and Ultra-Luminous Infrared Galaxies. Using the three most recent calculations of the non-blazar contribution to the extragalactic $\gamma$-ray background measured by the Fermi-LAT collaboration, we find that a hard power-law spectrum with spectral index $\alpha \leq 2.12$ is compatible with all the estimations for the allowed contribution from non-blazar sources, within 1$\sigma$. Using such a spectrum we are able to interpret the IceCube results, showing that various classes of hadronically powered $\gamma$-ray galaxies can provide the dominant contribution to the astrophysical signal above 100 TeV and about half of the contribution to the energy flux between 10-100 TeV. With the addition of neutrinos from the Galactic plane, it is possible to saturate the IceCube signal at high energy. Our result shows that these sources are still well motivated candidates.Comment: Accepted for publication on JCA

On the Putative Detection of z>0 X-ray Absorption Features in the Spectrum of Markarian 421

In a series of papers, Nicastro et al. have reported the detection of z>0 OVII absorption features in the spectrum of Mrk421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate this result in the context of a high quality spectrum of the same source obtained with the Reflection Grating Spectrometer (RGS) on XMM-Newton. The data comprise over 955ks of usable exposure time and more than 26000 counts per 50 milliAngstrom at 21.6 Angstroms. We concentrate on the spectrally clean region (21.3 < lambda < 22.5 Angstroms) where sharp features due to the astrophysically abundant OVII may reveal an intervening, warm--hot intergalactic medium (WHIM). We do not confirm detection of any of the intervening systems claimed to date. Rather, we detect only three unsurprising, astrophysically expected features down to the Log(N_i)~14.6 (3 sigma) sensitivity level. Each of the two purported WHIM features is rejected with a statistical confidence that exceeds that reported for its initial detection. While we can not rule out the existence of fainter, WHIM related features in these spectra, we suggest that previous discovery claims were premature. A more recent paper by Williams et al. claims to have demonstrated that the RGS data we analyze here do not have the resolution or statistical quality required to confirm or deny the LETGS detections. We show that our careful analysis resolves the issues encountered by Williams et al. and recovers the full resolution and statistical quality of the RGS data. We highlight the differences between our analysis and those published by Williams et al. as this may explain our disparate conclusions.Comment: 19 pages/7 figures/4 tables. 060424 submitted to ApJ 060522 re-submitted following ApJ reques

Chicago Alliance For Equity in Computer Science

CAFECS is committed to ensuring that all students in Chicago participate in engaging, relevant, and rigorous computing experiences by addressing problems of practice through research and development that increases opportunities for all students to pursue computing pathways and prepares all students for the future of work

Chicago Alliance For Equity in Computer Science

In 2016, CPS enacted a high school computer science graduation requirement as a means to broaden participation in computer science. ECS is the primary course that supports enactment of this policy. With limited numbers of certified computer science teachers, CPS relied on teachers from a variety of disciplines to teach ECS. The ECS professional development program is designed to prepare teachers from all backgrounds to support student success in ECS. This study examines how the profile of ECS teachers changed and the impact of that change on teachers\u27 experiences with ECS professional development

The Changing Profile of ECS Teachers

This study compares the characteristics and professional development (PD) experiences between teachers who began teaching Exploring Computer Science before and after the enactment of a CS graduation requirement in the Chicago Public Schools. The post-requirement teachers were less likely to have a CS background, but their experience in the ECS PD and their level of confidence at the end of the PD were equivalent to the early adopters

Chicago Alliance For Equity in Computer Science

Each year, about 14,000 Chicago Public Schools (CPS) students graduate with one year of high school computer science (CS) in fulfillment of the district’s CS graduation requirement. This accomplishment was the culmination of a decade of work by the Chicago Alliance for Equity in Computer Science (CAFÉCS), which includes CPS teachers and administrators, university CS faculty, and educational researchers. CAFÉCS research indicates that CPS significantly increased the capacity of schools to offer the Exploring Computer Science (ECS) introductory course, resulting in a rapid, equitable increase in students’ participation in CS. Making CS mandatory did not negatively impact performance in ECS. Students after the graduation requirement were also equally likely to be inspired to take additional CS coursework, thus doubling the number of students pursuing CS pathways. A large number of these students are now attending the City Colleges of Chicago with increased interest in CS. Recently, CAFÉCS launched a collaboration with Wright College (one of the City Colleges) and Mentor Collective to support students as they transition from CPS to the city colleges. A pilot group of 17 Wright College students are receiving peer mentoring from students at UIC and DePaul

Responding to Secondary Traumatic Stress: A Pilot Study of Torture Treatment Programs in the United States

Providers who care for torture survivors may be at risk for secondary traumatic stress, yet there has been little documentation of the effects of repeated exposure to traumatic issues on their emotional health or exploration of the support systems and resources available to address their emotional needs. This study assessed the secondary stress experiences of service providers (N = 43) within the National Consortium of Torture Treatment Programs in the United States and examined the supports offered by their organizations. The study found a significant correlation between rates of anxiety and depression among providers, r(34) = .49, p = .003. Although these participants reported that their work with survivors of torture was stressful, 91% indicated that their organizations offered a variety of stress-reduction activities. Overall, participants reported that their own personal activities were the most-effective stress reducers. The results are discussed in light of challenges that professionals who work with this population face and the effectiveness of support systems available to support their work

Study of access and outcomes from advanced computer science coursework in the Chicago Public Schools\u27\u27 poster in Structured Poster Session CS for All: An intersectional approach to unpacking equity in computer science education

The Chicago Public Schools (CPS) has taken a unique approach to broadening participation of low-income students, students of color, and girls by establishing Computer Science (CS) as a high school graduation requirement. This policy ensures that all CPS high school students will take a CS course, starting with the class of 2020. However, equity is more than just access. We define equity as equivalence in both the quality and outcomes of CS experiences. Exploring Computer Science (ECS) is the foundational course that fulfills the CPS requirement. Through ECS professional development, the number of qualified ECS teachers has grown. Two years into policy implementation, three-fourths of the schools offered ECS. Our prior research has shown that ECS participation rates by race, gender, and income closely reflect representation of the corresponding populations in CPS. In addition, student performance on the ECS end-of-course assessment was equivalent by race, gender, and income level. This evidence suggests that the CPS graduation policy is contributing towards equitable access to introductory CS with equitable course outcomes. Another outcome of interest is the equitable pursuit of advanced CS. Our primary research question for this poster is the extent to which there is equitable representation and outcomes of students who pursue advanced CS coursework in CPS. In particular, we focused on enrollment in the AP Computer Science A (CSA) and AP Computer Science Principles (CSP) courses from the 2014--15 to the 2017--18 school year. The 2014--15 school year was the first year that the CSP course was pilot tested in CPS, and the 2016--17 school year was the first year that the CSP exam was available. For every student enrolled in either AP CS course, the dataset included race, gender, special education status, English language learner status, free and reduced lunch status, overall GPA, AP course grade, and AP exam score. During the target period, enrollment in CSA declined from a high of 220 to a low of 136 students, while CSP enrollment increased from a pilot of 29 students to 693 students. The combined representation of students by race and gender in both courses was not reflective of the district\u27s student demographics. However, student representation by race and gender was closer to the district representation for CSP than for CSA. We conducted a multiple regression of the factors that correlated with the AP exam performance. The students\u27 overall GPA and the grade in the course were significantly correlated with exam scores. Girls scored statistically lower than boys and Latinx students scored statistically lower than Caucasian, Asian, and African-American students. Students who took ECS prior to CSP scored statistically higher on the CSP exam. These results show promise that using ECS as a foundation course is helpful for students who go on to pursue AP CSP. However, more work needs to be done to capitalize on the success of ECS to encourage CPS schools to offer AP CS courses and to encourage girls and students from underrepresented minority groups to pursue advanced CS coursework