Adolescent identity development is driven to a significant degree by peer interaction. However, when mental health conditions (MHC) or other crises separate teens from their peers, their identity ...development can be slowed or arrested. We developed a unique open studio intervention (OS-ID) that could facilitate identity development in teens recovering from MHC, and incorporated this intervention into a therapeutic day school catering to our target population. We utilized qualitative case study research to explore these students’ experiences. Over the 10-month period of our intervention, we saw positive changes in the participants’ identity development. Key elements in OS-ID include the therapists’ commitment to supported autonomy; the absence of participatory demands; the emphasis on creative process over product; the use of setting and materials to promote the healing process; the facilitators’ and participants’ witnessing the process; the privatization and protection of the participants’ creations; and the ubiquitous presence of non-threatening significant others. This OS-ID modality could be an effective mechanism for assisting socially isolated teens to manage their social anxiety, develop their identity, and transition back into their peer environments.
ABSTRACT We present extensive optical (UBV RI, , and open CCD) and near-infrared (ZY JH) photometry for the very nearby Type IIP SN 2013ej extending from +1 to +461 days after shock breakout, ...estimated to be MJD 56496.9 0.3. Substantial time series ultraviolet and optical spectroscopy obtained from +8 to +135 days are also presented. Considering well-observed SNe IIP from the literature, we derive UBV RIJHK bolometric calibrations from UBV RI and unfiltered measurements that potentially reach 2% precision with a B − V color-dependent correction. We observe moderately strong Si ii as early as +8 days. The photospheric velocity ( ) is determined by modeling the spectra in the vicinity of Fe ii whenever observed, and interpolating at photometric epochs based on a semianalytic method. This gives km s−1 at +50 days. We also observe spectral homogeneity of ultraviolet spectra at +10-12 days for SNe IIP, while variations are evident a week after explosion. Using the expanding photosphere method, from combined analysis of SN 2013ej and SN 2002ap, we estimate the distance to the host galaxy to be Mpc, consistent with distance estimates from other methods. Photometric and spectroscopic analysis during the plateau phase, which we estimated to be 94 7 days long, yields an explosion energy of erg, a final pre-explosion progenitor mass of 15.2 4.2 and a radius of 250 70 . We observe a broken exponential profile beyond +120 days, with a break point at +183 16 days. Measurements beyond this break time yield a 56Ni mass of 0.013 0.001 M .
ABSTRACT The overtone and multi-mode RR Lyrae stars in the globular cluster M3 are studied using a 200 day long, , and time-series photometry obtained in 2012. 70% of the 52 overtone variables ...observed show some kind of multi-periodicity (with additional frequency at frequency ratio, Blazhko effect, double/multi-mode pulsation, and period doubling). A signal at the 0.587 frequency ratio to the fundamental-mode frequency is detected in the double-mode star, V13, which may be identified as the second radial overtone mode. If this mode identification is correct, than V13 is the first RR Lyrae star showing triple-mode pulsation of the first three radial modes. Either the Blazhko effect or the frequency (or both of these phenomena) appears in seven double-mode stars. The period ratio of RRd stars showing the Blazhko effect are anomalous. A displacement of the main frequency component at the fundamental mode with the value of modulation frequency (or its half), is detected in three Blazhko RRd stars that are parallel with the appearance of the overtone-mode pulsation. The frequency appears in RRc stars that lie at the blue side of the double-mode region and in RRd stars, raising the suspicion that its occurrence may be connected to double-mode pulsation. The changes of the Blazhko and double-mode properties of the stars are also reviewed using the recent and archive photometric data.
The period-change behaviour of 134 RR Lyrae stars in the globular cluster Messier 3 (M3) is investigated on the ∼120 yr time-base of the photometric observations. The mean period-change rates (β≈ ...0.01 d Myr−1) of the subsamples of variables exhibiting the most regular behaviour are in good agreement with theoretical expectations based on horizontal branch stellar evolution models. However, a large fraction of variables show period changes that contradict the evolutionary expectations. Among the 134 stars studied, the period-change behaviour of only 54 variables is regular (constant or linearly changing), slight irregularities are superimposed on the regular variations in 23 cases and the remaining 57 stars display irregular period variations. The light curve of ∼50 per cent of the RRab stars is not stable, that is, these variables exhibit Blazhko modulation. The large fraction of variables with peculiar behaviour (showing light-curve modulation and/or irregular O−C variation) indicates that, probably, variables with regular period changes incompatible with their evolutionary stages also could display some kind of instability of the pulsation light curve and/or period, but the available observations have not disclosed it yet. The temporal appearance of the Blazhko effect in some stars, and the 70-90 yr long regular changes preceded or followed by irregular, rapid changes of the pulsation period in some cases, supports this hypothesis.
Accurate Fourier parameters of the light curves of the RRab variables are derived from all the available CCD data. The large, homogeneous sample of stars on the Oosterhoff I sequence enable us to investigate the characteristics of the light curves of the variables showing increasing and decreasing period changes. It is found that, at a given phase-difference value, period-increasing variables have 0.002-0.014 mag smaller amplitudes on average than period-decreasing variables have. Also, at a given period, their phase differences tend to be smaller by 0.03-0.07 rad than the phase differences of variables with decreasing periods. The realness of the detected differences is proven by Monte Carlo simulations.
Abstract
We present the first simultaneous photometric and spectroscopic investigation of a large set of RR Lyrae variables in a globular cluster. The radial-velocity (RV) data presented comprise the ...largest sample of RVs of RR Lyrae stars ever obtained. The target is M3; BVIC time series of 111 and b flux data of further 64 RRab stars and RV data of 79 RR Lyrae stars are published. Blazhko modulation of the light curves of 47 per cent of the RRab stars is detected. The mean value of the centre-of-mass velocities of RR Lyrae stars is −146.8 km s−1 with 4.52 km s−1 standard deviation, which is in good agreement with the results obtained for the red giants of the cluster. The Φ21RV phase difference of the RV curves of RRab stars is found to be uniformly constant both for the M3 and for Galactic field RRab stars; no period or metallicity dependence of the Φ21RV is detected. The Baade–Wesselink distances of 26 non-Blazhko variables with the best phase-coverage RV curves are determined; the corresponding distance of the cluster, 10 480 ± 210 pc, agrees with the previous literature information. A quadratic formula for the Apuls − AV relation of RRab stars is given, which is valid for both OoI and OoII variables. We also show that (V − I)0 of RRab stars measured at light minimum is period dependent; there is at least 0.1 mag difference between the colours at minimum light of the shortest and longest period variables.
V582 Aur is an FU Ori-type young eruptive star in outburst since ∼1985. The eruption is currently in a relatively constant plateau phase, with photometric and spectroscopic variability superimposed. ...Here we will characterize the progenitor of the outbursting object, explore its environment, and analyze the temporal evolution of the eruption. We are particularly interested in the physical origin of the two deep photometric dips, one that occurred in 2012 and one that is ongoing since 2016. We collected archival photographic plates and carried out new optical, infrared, and millimeter-wave photometric and spectroscopic observations between 2010 and 2018, with a high sampling rate during the current minimum. Besides analyzing the color changes during fading, we compiled multiepoch spectral energy distributions and fitted them with a simple accretion disk model. Based on pre-outburst data and a millimeter continuum measurement, we suggest that the progenitor of the V582 Aur outburst is a low-mass T Tauri star with average properties. The mass of an unresolved circumstellar structure, probably a disk, is 0.04 M . The optical and near-infrared spectra demonstrate the presence of hydrogen and metallic lines, show the CO band head in absorption, and exhibit a variable H profile. The color variations strongly indicate that both the ∼1 yr long brightness dip in 2012 and the current minimum since 2016 are caused by increased extinction along the line of sight. According to our accretion disk models, the reddening changed from AV = 4.5 to 12.5 mag, while the accretion rate remained practically constant. Similarly to the models of the UXor phenomenon of intermediate- and low-mass young stars, orbiting disk structures could be responsible for the eclipses.
Context. The sudden optical brightening of two young stellar objects, HBC 722 and VSX J205126.1+440523, located in the North America/Pelican Nebula Complex, was announced in August 2010. Early ...photometric and spectroscopic observations of these objects indicated that they may belong to the FUor or EXor class of young eruptive stars. The eruptions of FUors and EXors are often explained by enhanced accretion of material from the circumstellar disk to the protostar. Aims. In order to determine the true nature of these two objects, we started an optical and near-infrared monitoring program, and complemented our data with archival observations and data from the literature. Methods. We plot and analyze pre-outburst and outburst spectral energy distributions (SEDs), multi-filter light curves, and color–color diagrams. Results. The quiescent SED of HBC 722 is consistent with that of a slightly reddened normal T Tauri-type star. The source brightened monotonically in about two months, and the SED obtained during maximum brightness indicates the appearance of a hot, single-temperature blackbody. The current fading rate implies that the star will return to quiescence in about a year, which questions its classification as a bone fide FUor. The quiescent SED of VSX J205126.1+440523 looks like that of a highly embedded Class I source. The outburst of this source happened more gradually, but reached an unprecedentedly high amplitude. Its light curves showed a deep minimum two and a half months after the peak, when the object was close to its pre-outburst optical brightness. Further monitoring indicates that it is still far from being quiescent. Conclusions. The shape of the light curves as well as the bolometric luminosities and accretion rates suggest that these objects do not fit into the classic FUor group. Although HBC 722 exhibits all spectral characteristics of a bona fide FUor, its luminosity and accretion rate is too low and its timescale is too fast compared with classical FUors. VSX J205126.1+440523 seems to be an example where quick extinction changes modulate the light curve.
Long-duration gamma-ray bursts (GRBs) are widely believed to be highly collimated explosions (bipolar conical outflows with half-opening angle theta{approx} 1{sup 0}-10{sup 0}). As a result of this ...beaming factor, the true energy release from a GRB is usually several orders of magnitude smaller than the observed isotropic value. Measuring this opening angle, typically inferred from an achromatic steepening in the afterglow light curve (a 'jet' break), has proven exceedingly difficult in the Swift era. Here, we undertake a study of five of the brightest (in terms of the isotropic prompt gamma-ray energy release, E{sub g}amma{sub ,iso}) GRBs in the Swift era to search for jet breaks and hence constrain the collimation-corrected energy release. We present multi-wavelength (radio through X-ray) observations of GRBs 050820A, 060418, and 080319B, and construct afterglow models to extract the opening angle and beaming-corrected energy release for all three events. Together with results from previous analyses of GRBs 050904 and 070125, we find evidence for an achromatic jet break in all five events, strongly supporting the canonical picture of GRBs as collimated explosions. The most natural explanation for the lack of observed jet breaks from most Swift GRBs is therefore selection effects. However, the opening angles for the events in our sample are larger than would be expected if all GRBs had a canonical energy release of {approx}10{sup 51} erg. The total energy release we measure for the 'hyper-energetic' (E{sub tot} {approx}> 10{sup 52} erg) events in our sample is large enough to start challenging models with a magnetar as the compact central remnant.
We present a comparative study of absolute distances to a sample of very nearby, bright Type Ia supernovae (SNe) derived from high cadence, high signal-to-noise, multi-band photometric data. Our ...sample consists of four SNe: 2012cg, 2012ht, 2013dy and 2014J. We present new homogeneous, high-cadence photometric data in Johnson-Cousins BVRI and Sloan g′r′i′z′ bands taken from two sites (Piszkesteto and Baja, Hungary), and the light curves are analyzed with publicly available light curve fitters (MLCS2k2, SNooPy2 and SALT2.4). When comparing the best-fit parameters provided by the different codes, it is found that the distance moduli of moderately reddened SNe Ia agree within 0.2 mag, and the agreement is even better ( 0.1 mag) for the highest signal-to-noise BVRI data. For the highly reddened SN 2014J the dispersion of the inferred distance moduli is slightly higher. These SN-based distances are in good agreement with the Cepheid distances to their host galaxies. We conclude that the current state-of-the-art light curve fitters for Type Ia SNe can provide consistent absolute distance moduli having less than ∼0.1-0.2 mag uncertainty for nearby SNe. Still, there is room for future improvements to reach the desired ∼0.05 mag accuracy in the absolute distance modulus.
Context. V2492 Cyg is a young eruptive star that went into outburst in 2010. The near-infrared color changes observed since the outburst peak suggest that the source belongs to a newly defined ...sub-class of young eruptive stars, where time-dependent accretion and variable line-of-sight extinction play a combined role in the flux changes. Aims. In order to learn about the origin of the light variations and to explore the circumstellar and interstellar environment of V2492 Cyg, we monitored the source at ten different wavelengths, between 0.55 μm and 2.2 μm from the ground and between 3.6 μm and 160 μm from space. Methods. We analyze the light curves and study the color−color diagrams via comparison with the standard reddening path. We examine the structure of the molecular cloud hosting V2492 Cyg by computing temperature and optical depth maps from the far-infrared data. Results. We find that the shapes of the light curves at different wavelengths are strictly self-similar and that the observed variability is related to a single physical process, most likely variable extinction. We suggest that the central source is episodically occulted by a dense dust cloud in the inner disk and, based on the invariability of the far-infrared fluxes, we propose that it is a long-lived rather than a transient structure. In some respects, V2492 Cyg can be regarded as a young, embedded analog of UX Orionis-type stars. Conclusions. The example of V2492 Cyg demonstrates that the light variations of young eruptive stars are not exclusively related to changing accretion. The variability provided information on an azimuthally asymmetric structural element in the inner disk. Such an asymmetric density distribution in the terrestrial zone may also have consequences for the initial conditions of planet formation.
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