Historical Light Research Articles

Carbon markets: a historical overview

AbstractThe global carbon trade has in a short space of time grown into a market worth over $175 billion a year. The history of carbon markets is a great political success story, and today they form an integral part of international climate change policy. Yet we only have a very limited understanding of how well these markets work in practice. Studying the incoming evidence and piecing it together with past emissions trading experiences can teach us a lot about how carbon markets work, and how they can fail. This article reviews the history of emissions trading and the rise of carbon markets as a basis for better understanding what is happening now. Viewing these markets in a historical light reveals that many of the current problems have precedent, and that we are perhaps not learning enough from past experiences. If carbon market policies were more geared toward systematic evaluation, and more open to incorporating past lessons into new policy, carbon markets would stand a greater chance of helping achieve the transition to a low‐carbon economy. WIREs Clim Change 2013, 4:107–119. doi: 10.1002/wcc.208This article is categorized under: The Carbon Economy and Climate Mitigation > Policies, Instruments, Lifestyles, Behavior

PRECURSOR FLARES IN OJ 287

We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending towards the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z_c = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.

A model for the 19th century eruption of Eta Carinae: CSM interaction like a scaled-down Type IIn Supernova

This paper proposes a simple model for the 19th century eruption of Eta Carinae that consists of two components: (1) a strong wind (MdotM=0.33 Msun/yr; v=200 km/s), blowing for 30 years, followed by (2) a 1e50 erg explosion in 1844. The ensuing collision between the fast ejecta and the CSM causes an increase in brightness observed at the end of 1844, followed by a sustained high-luminosity phase lasting for 10-15 years that matches the historical light curve. The emergent luminosity is powered by CSM interaction, analogous to the process in luminous Type IIn supernovae, except with 10 times lower explosion energy and at slower speeds (causing a longer duration and lower emergent luminosity). Such an explosive event provides a natural explanation for the light curve evolution, but also accounts for a number of puzzling attributes of the Homunculus nebula: (1) rough equipartition of total radiated and kinetic energy, (2) the double-shell structure of the Homunculus, (3) the apparent single age and Hubble-like flow resulting from the thin swept-up shell, (4) the complex mottled appearance of the polar lobes in HST images, arising from Raleigh-Taylor or Vishniac instabilities, (5) efficient and rapid dust formation, as seen in Type IIn supernovae, and (6) the fast (5000 km/s) material outside the Homunculus, arising from the acceleration of the forward shock upon exiting the dense CSM. In principle, the bipolar shape has already been explained in earlier studies of interacting winds, except that here the CSM interaction occurs over only 10 years, producing a thin shell with the resulting structures then frozen-in to the expanding bipolar nebula. This self-consistent picture has a number of implications for other eruptive transients, many of which may also be powered by CSM interaction.

The intellectual and institutional properties of learning: Historical reflections on patronage, autonomy, and transaction

This paper attempts to cast a little historical light on current debate among scholars and publishers that appears to be over whether the academic journal is an endlessly exploitable commercial property or a public good to which all have right. It identifies key patterns in the patronage of medieval monasticism that helped to establish learning as an economically distinct form of labor, and is part of a larger historical project on the intellectual and institutional properties of learning in the West. Through the beneficence shown toward monasteries by the nobility and others, learned nuns and monks were able to operate with a degree of autonomy and trust in their scholarly work. The resulting manuscripts were directed toward the learning of others and, as such, were copied and circulated widely within the admittedly narrow confines of the monastic community. These scholarly labors became part of what attracted the continuing gifts of benefactors, who were prepared to direct a portion of their wealth to this expression of piety and discipline. This paper reflects, then, on institutional conditions that proved vital to the advancement of learning in the centuries leading up to the emergence of the university system in the Late Middle Ages. As such, it forms a point of historical reflection for the academic community today, as it reconsiders the principles by which research and scholarship should circulate within the new possibilities posed by the digital era.

A HOLISTIC VIEW OF THE W UMA TYPE TY BOO

New CCD four-color light curves of TY Boo made on eight nights over 2010-2011 were analyzed in comparison with historical light curves obtained from 1969 through 2011. The light curves could all be represented by a unique geometry and by wavelength consistent phototometric parameters of a two-spot model on either stellar component. It is confirmed that TY Boo is a shallow W-type contact binary system with a degree of contact factor of f = 7.6% ({+-}0.8). A period investigation based on all available data shows a long-term decrease (dP/dt = -3.65 Multiplication-Sign 10{sup -8} days yr{sup -1}) and an oscillation (P{sub 3} = 58.9 yr, A = 0.0254 days). Without ruling out the presence of a tertiary companion, the weight of evidence points to an active cyclic magnetic activity that causes spot formation rather than an unseen companion. Mass transfer between the components and angular momentum loss are also considered as possible mechanisms.

The evolving notion of relevance: an historical perspective to the ‘economics made fun’ movement

This paper aims to study the ‘economics made fun’ literature with regard to its main purpose: popularizing economics. We shed an historical light on such literature by showing that its main strategy for introducing economics to non-specialists had already been tried in the 1970s in what were described as “issues-oriented” textbooks. We show that both literatures, as introductory enterprises, were responses to similar challenges. The first one is the problem of economic illiteracy, a problem that has concerned teachers in economics since the early 1960s. Both literatures did offer an interesting response to perceived shortcomings of introductory courses. The second challenge came from the attacks on economics and its teaching for their lack of relevance. We explore how the notion of relevance evolved in time and how both literatures attempted to respond to the criticisms of their time accordingly. By addressing these questions, our study explores how economists used these introductory enterprises to disseminate a certain image of them and their discipline in comparison to other social scientists and non-specialists, and how these representations evolved in time.

A “Great Experiment” of the League of Nations Era: International Nongovernmental Organizations, Global Governance, and Democracy Beyond the State

This article aims to shed historical light on the contemporary debate concerning the role of international nongovernmental organizations and intergovernmental organizations in the democratization of global governance through an assessment of the experience and political thought of the League of Nations era. After introducing the interactions of international nongovernmental organizations and intergovernmental organizations in the present day and in the League of Nations period and the contemporary debate on their role in the democratization of global governance, the article discusses how democracy in global governance was conceived in the League of Nations era, with particular reference to the work of Alfred Zimmern. The analysis highlights not only the considerable continuities between interwar thought and that of the present day, but also the potential problems identified at the time that remain pertinent today.

Reconstructing Historical Light Curves of Symbiotic Stars and Novae

Abstract We reconstructed photometric histories of symbiotic stars and novae from direct inspection and measurement of photographic plates preserved at historical archives. We have completed the digging of the rich Asiago archive, and have started working on the Harvard plate stack, while other plate collections should be added soon. For homogeneity, we use the same UBV RCIC photometric comparison sequences used in current CCD observations. This data harvest has permitted the discovery of past undetected outbursts and secular trends, or to derive previously unknown orbital periods and recurrence times, which are essential to constrain the nature of these capricious and variegated active binaries.

Optical photometric and spectral study of the new FU Orionis object V2493 Cygni (HBC 722)

We present new results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V2493 Cyg (HBC 722). The object has continued to undergo significant brightness variations over the past few months and is an ideal target for follow-up observations. We carried out CCD BVRI photometric observations in the field of V2493 Cyg ("Gulf of Mexico") from August 1994 to April 2012, i.e. at the pre-outburst states and during the phases of the outburst. We acquired high, medium, and low resolution spectroscopy of V2493 Cyg during the outburst. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. Both CCD and photographic observations were analyzed using 15 comparison stars in the field of V2493 Cyg. The pre-outburst photographic and CCD photometric observations of V2493 Cyg show low-amplitude light variations typical of T Tauri stars. The recent photometric data show a slow light decrease from October 2010 to June 2011 followed by an increase in brightness that continued until early 2012. The spectral observations of V2493 Cyg are typical of FU Orionis stars absorption spectra with strong P Cyg profiles of H alpha and Na I D lines. On the basis of photometric monitoring performed over the past two years, the spectral properties at the maximal light, as well as the shape of long-term light curves, we confirm that the observed outburst of V2493 Cyg is of FU Orionis type.

Factors in the Soviet Decision to Invade Czechoslovakia

This essay describes the factors in the Soviet decision to invade Czechoslovakia and argues that the principle motive was to prevent political reforms which would have established Czechoslovakia as multi-party state. The paper will be organized in three parts: after establishing factual background of the ̳Prague Spring‘ reforms, the essay outlines the various factors contributing to the decision. I will then analyze them in comparative historical light in order to single out the most important reason for the invasion.

Gone and forgotten: where has the “literature” gone?

Gone and forgotten: where has the “literature” gone?

The historical light curve of the symbiotic star AG Draconis: intense, magnetically induced cyclic activity

We analyze an optical light curve of the symbiotic system AG Draconis covering the last 120 years of its history. During the first 32 years the system was in a quiescence state. Around the year 1922 the star's quiescence luminosity brightened by 0.29 mag. The last 82 years of the light curve (LC) are characterized by a series of outbursts of 1-2 magnitude in brightness and about 100 days in duration. The outbursts are distributed along the time axis in 6 clusters with a quasi-periodic cycle of some 5300 days. The time intervals among the outbursts themselves are integral numbers of the period 373.5 days. During quiescence states the LC oscillates with the binary period of the system of 550 d. The LC contains also a weak periodic signal with a period of 350 d, attributed to pulsations of the giant star. Another period of 1160 d is also present in the light curve, being the sidereal rotation period of the giant star. We suggest that the outbursts are events of intense mass transfer from the giant onto the hot component. These are modulated by an interplay between a solar-like magnetic dynamo cycle operating in the outer layers of the giant, and a tidal deformation of these layers that circulates the surface of the giant with the synodic diurnal period of 373.5 Earth days. AG Dra is the 5th symbiotic system with a light curve that reflects such an intense magnetic and magnetically modulated activity. (Abridged)

Intraday optical variability of the BL Lacertae object S5 0716+714

The intraday optical variability of the BL Lacertae object S5 0716+714 is studied using historical light curves. The well-sampled intranight data set is selected. In total, 19 333 data points have been collected over 208 nights. The source exhibits strong variability in the optical band. At a confidence level of 99.9 per cent, for 162 of the 208 nights the source shows intranight variability. The source varies with an increasing rate of 0.043 mag h-1 and a decreasing rate of 0.036 mag h-1 during the observations, with no evident difference between rising and falling parts. The fast variability is found on JD 245 1909, with a decreasing rate of 0.015 mag min-1 over 6 min. The temporal characteristic is studied by using the structure function method. The result shows that the source varies with an 11.5-min time-scale. For this source, the emission size is estimated to be 1.39 x 1014 cm, the mass of the central black hole is estimated to be 107.87 M? and the magnetic field strength is estimated to be 10.6 G.

PTF10iya: a short-lived, luminous flare from the nuclear region of a star-forming galaxy

We present the discovery and characterisation of PTF10iya, a short-lived (dt ~ 10 d, with an optical decay rate of ~ 0.3 mag per d), luminous (M_g ~ -21 mag) transient source found by the Palomar Transient Factory. The ultraviolet/optical spectral energy distribution is reasonably well fit by a blackbody with T ~ 1-2 x 10^4 K and peak bolometric luminosity L_BB ~ 1-5 x 10^44 erg per s (depending on the details of the extinction correction). A comparable amount of energy is radiated in the X-ray band that appears to result from a distinct physical process. The location of PTF10iya is consistent with the nucleus of a star-forming galaxy (z = 0.22405 +/- 0.00006) to within 350 mas (99.7 per cent confidence radius), or a projected distance of less than 1.2 kpc. At first glance, these properties appear reminiscent of the characteristic "big blue bump" seen in the near-ultraviolet spectra of many active galactic nuclei (AGNs). However, emission-line diagnostics of the host galaxy, along with a historical light curve extending back to 2007, show no evidence for AGN-like activity. We therefore consider whether the tidal disruption of a star by an otherwise quiescent supermassive black hole may account for our observations. Though with limited temporal information, PTF10iya appears broadly consistent with the predictions for the early "super-Eddington" phase of a solar-type star disrupted by a ~ 10^7 M_sun black hole. Regardless of the precise physical origin of the accreting material, the large luminosity and short duration suggest that otherwise quiescent galaxies can transition extremely rapidly to radiate near the Eddington limit; many such outbursts may have been missed by previous surveys lacking sufficient cadence.

What Impact does Background have on Initial Teacher Trainees’ Conceptions of Teaching History to Primary School Pupils?

This article arises from a project on the nature of primary school teachers’ initial conceptions of historical learning. There was a sense from the author’s situated practice that trainees’ perceptions of what constitutes worthwhile learning about history is determined in significant part by their backgrounds and primarily their experiences of being taught history at school. Given the limited experience of formal history education for many trainees beyond the age of fourteen, background or the lack of background exposure seemed to have a significant influence in determining conceptions of history. Paired interviews of trainees were undertaken to ascertain their memories of being taught history. The trainees were also asked to comment on their own approaches to working with historical sources to help cast light on whether these conceptions influenced their approach to teaching and learning about primary history. Their answers appeared to demonstrate the way that prior learning can shape prospective teachers’ approaches to teaching history. It may also indicate the need for continued professional development for trainees and newly qualified teachers to give them more powerful conceptions of disciplinary approaches to teaching and learning the subject.

On the damage of frescoes and stuccoes on the lower surface of historical flat suspended light vaults

Abstract In many historical and monumental Italian buildings, frescoes or stuccoes of artistic and historical value are present on the lower surface of flat light vaults, made by wooden arches, reeds and plaster. These vaults are often suspended by wooden or metallic ties to the upper bearing structures. When differential settlements of the wooden arches happen (i.e.: due to a bad working of their hangings) cracks appear on these precious surfaces. This paper experimentally and numerically investigates on this issue, pointing out which constructive parameters mainly influence the cracking behaviour of the frescoed or stuccoed lower surface, and thus providing guide lines for designing compatible conservation and retrofitting interventions.

Historical light curve and search for previous outbursts of Nova KT Eridani (2009)

Context. Nova Eridani (2009) caught the eye of the nova community due to its fast decline from maximum, which was initially missed, and its subsequent development in the radio and X-ray wavelengths. This system also exhibits properties similar to those of the much smaller class of recurrent novae; themselves potential progenitors of Type Ia Supernovae. Aims. We aim to determine the nature and physical parameters of the KT Eri progenitor system. Methods. We searched the Harvard College Observatory archive plates for the progenitor of KT Eri to determine the nature of the system, particularly the evolutionary stage of the secondary.We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale. Furthermore, by comparing the colours of the quiescent system on a colour-magnitude diagram we may infer the nature of the secondary star. Results. We identified the progenitor system of KT Eri and measured a quiescent magnitude of < B >= 14.7 \pm 0.4. No previous outburst was found. However, we suggest that if the nova is recurrent it should be on a timescale of centuries. We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary. The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in, or ascending, the Red Giant Branch. A second period is evident at 376 days which has a sinusoidal like light curve. Furthermore, the outburst amplitude of ~ 9 magnitudes is inconsistent with those expected for fast classical novae (~ 17 magnitudes) which may lend further support for an evolved secondary. (Abridged)

WZ Cephei: A Dynamically Active W UMa-Type Binary Star

An intensive analysis of 185 timings of WZ Cep, including our new three timings, was made to understand the dynamical picture of this active W UMa-type binary. It was found that the orbital period of the system has complexly varied in two cyclical components superposed on a secularly downward parabola over about 80y. The downward parabola, corresponding to a secular period decrease of <TEX>$-9.{^d}97{\times}10^{-8}y^{-1}$</TEX>, is most probably produced by the action of both angular momentum loss (AML) due to magnetic braking and mass-transfer from the massive primary component to the secondary. The period decrease rate of <TEX>$-6.^{d}72{\times}10^{-8}y^{-1}$</TEX> due to AML contributes about 67% to the observed period decrease. The mass flow of about <TEX>$5.16{\times}10^{-8}M_{\odot}y^{-1}$</TEX> from the primary to the secondary results the remaining 33% period decrease. Two cyclical components have an <TEX>$11.^{y}8$</TEX> period with amplitude of <TEX>$0.^{d}0054$</TEX> and a <TEX>$41.^{y}3$</TEX> period with amplitude of <TEX>$0.^{d}0178$</TEX>. It is very interesting that there seems to be exactly in a commensurable 7:2 relation between their mean motions. As the possible causes, two rival interpretations (i.e., light-time effects (LTE) by additional bodies and the Applegate model) were considered. In the LTE interpretation, the minimum masses of <TEX>$0.30M_{\odot}$</TEX> for the shorter period and <TEX>$0.49M_{\odot}$</TEX> for the longer one were calculated. Their contributions to the total light were at most within 2%, if they were assumed to be main-sequence stars. If the LTE explanation is true for the WZ Cep system, the 7:2 relation found between their mean motions would be interpreted as a stable 7:2 orbit resonance produced by a long-term gravitational interaction between two tertiary bodies. In the Applegate model interpretation, the deduced model parameters indicate that the mechanism could work only in the primary star for both of the two period modulations, but could not in the secondary. However, we couldn't find any meaningful relation between the light variation and the period variability from the historical light curve data. At present, we prefer the interpretation of the mechanical perturbation from the third and fourth stars as the possible cause of two cycling period changes.

NSV 11154 Is a New R Coronae Borealis Star

ABSTRACTNSV 11154 has been confirmed as a new member of the rare hydrogen-deficient R Coronae Borealis (RCB) stars based on new photometric and spectroscopic data. Using new photometry, as well as archival plates from the Harvard archive, we have constructed the historical light curve of NSV 11154 from 1896 to the present. The light curve shows the sudden, deep, irregularly spaced declines characteristic of RCB stars. The visible spectrum is typical of a cool (Teff ≲ 5000 K) RCB star, showing no hydrogen lines, strong C2 Swan bands, and no evidence of 13C. In addition, the star shows small pulsations that are typical of an RCB star and an infrared excess due to circumstellar dust, with a temperature of ∼800 K. The distance to NSV 11154 is estimated to be ∼14.5 kpc. RCB stars are very rare in the Galaxy, so each additional star is important to population studies leading to a better understanding the origins of these mysterious stars. Among the known sample of RCB stars, NSV 11154 is unusual in that it lies well above the Galactic plane (5 kpc) and away from the Galactic center, which suggests that its parent population is neither thick disk nor bulge.

A revised historical light curve of Eta Carinae and the timing of close periastron encounters

The historical light curve of the 19th century ‘Great Eruption’ of η Carinae provides a striking record of the violent instabilities encountered by massive stars. In this paper, we report and analyse newly uncovered historical estimates of the visual brightness of η Car during its eruption, and we correct some mistakes in the original record. The revised historical light curve looks substantially different from previous accounts; it shows two brief precursor eruptions in 1838 and 1843 that resemble modern supernova impostors, while the final brightening in 1844 December marks the time when η Car reached its peak brightness. We consider the timing of brightening events as they pertain to the binary system in η Car. (1) The brief 1838 and 1843 events rose to peak brightness within weeks of periastron passages if the pre-1845 orbital period was ∼5 per cent shorter than that at present due to the mass-loss of the eruption. Each event lasted only ∼100 d. (2) The main brightening at the end of 1844 has no conceivable association with periastron, beginning suddenly more than 1.5 yr after periastron. It lasted ∼10 yr, with no obvious influence of periastron encounters during that time. (3) The 1890 eruption began to brighten at periastron, but took over 1 yr to reach maximum brightness and remained there for almost 10 yr. A second periastron passage mid-way through the 1890 eruption had no visible effect. While the evidence for a link between periastron encounters and the two brief precursor events is compelling, the differences between the three cases above make it difficult to explain all three phenomena with the same mechanism.