Recent H-alpha results on pulsar B2224+65's bow-shock nebula, the "Guitar"

We used the 4 m Discovery Channel Telescope (DCT) at Lowell observatory in 2014 to observe the Guitar Nebula, an Hα bow-shock nebula around the high-velocity radio pulsar B2224+65. Since the nebula`s discovery in 1992, the structure of the bow-shock has undergone significant dynamical changes. We have observed the limb structure, targeting the "body" and "neck" of the guitar. Comparing the DCT observations to 1995 observations with the Palomar 200-inch Hale telescope, we found changes in both spatial structure and surface brightness in the tip, head, and body of the nebula

Improving livelihoods, training para-ecologists, enthralling children: Earning trust for effective community- based biodiversity conservation in Andasibe, eastern Madagascar

The rainforests of eastern Madagascar are shrinking due to population growth, poverty-driven land degradation and widespread ignorance of ecological dynamics. This has resulted in large-scale transformation and fragmentation of these forests, threatening their unique biodiversity. Many of these problems are also manifest in and around the village of Andasibe. Based on the example of Association Mitsinjo, and drawing from more than a decade of experience of community-based natural resource management in Andasibe, we highlight the challenges and successes of a community-run conservation organization that builds trust through a holistic approach resting on five building blocks: (i) management transfer of natural resources to the local community, (ii) community-based nature tourism, (iii) training of para-scientists, (iv) rainforest restoration and improving local livelihoods, and (v) environmental education. This has resulted in the creation and legal protection of two community-run reserves, Analamazaotra and Torotorofotsy, accompanied by ecological monitoring programs. We illustrate how handing over responsibilities to local communities can be a promising approach to conserving natural resources and biodiversity in Madagascar and elsewhere. La superficie des forêts tropicales de l’est de Madagascar diminue avec la croissance démographique, la dégradation des terres par effet de la pauvreté, ainsi que par l'ignorance générale des interrelations écologiques. Tout cela a abouti à une transformation profonde et étendue ainsi qu’à la fragmentation de ces forêts qui menacent leur biodiversité. Ces problèmes globaux sont pour la plupart rencontrés à la périphérie du village d'Andasibe. Ici, l’exemple de l'Association Mitsinjo est présenté avec plus d’une décennie d’expérience en gestion communautaire des ressources naturelles à Andasibe. Sont ainsi exposés les défis et les succès d'une organisation de conservation gérée par la communauté qui gagne la confiance à travers une approche posée sur cinq piliers]: (i) le transfert de gestion des ressources naturelles à la communauté locale, (ii) l’écotourisme à base communautaire, (iii) la formation de para-scientifiques, (iv) la restauration de la forêt tropicale humide en augmentant les moyens de subsistance des gens vivant sur la périphérie, et (v) l’éducation environnementale. Les actions entreprises ont abouti à la création et la protection efficace de deux réserves gérées par la communauté, accompagnées de programmes de surveillance écologique. Grâce à la responsabilisation des collectivités locales dans la protection de la biodiversité, elles montrent une fierté des actions entreprises qui est un indice prometteur pour la conservation des ressources naturelles et de la biodiversité à Madagascar et ailleurs

Toponyms for centers of endemism in Madagascar

A biogeographical model was proposed in 2006 to explain the centers of endemism and the importance of riparian forest of some watersheds as refuges or dispersal corridors during paleoclimatic oscillations. Here, we consider these geographical features highlighting their biological and socio-cultural importance. We explain the etymology or eponymy of the major rivers of the retreat - dispersal watersheds, i.e., the drainage basins of Bemarivo, Antainambalana, Mangoro, Manampatrana, Mananara South, Mandrare, Onilahy, Mangoky, Tsiribihina, Betsiboka, Maevarano, Sambirano, and Mahavavy North. We propose a toponymy for each of the 15 centers of endemism and highlight their peculiarities. We named the centers of endemism of Vohimarina, Masoala, Analanjirofo, Tanala, Manombo, Anosy, Ranopiso, Karimbola, Mikea, Menabe, Melaky, Sofia, Ampasindava, Ankify, and Ankarana. We illustrate each center of endemism with a flagship species and report on its natural and cultural histories, and conservation.RÉSUMÉUn modèle biogéographique a été proposé en 2006 pour expliquer les centres d’endémisme de la biodiversité et l’importance des ripisylves de certains bassins versants en tant que refuges ou couloirs de dispersion au cours des oscillations paléoclimatiques. Ici, nous considérons ces dispositifs géographiques en soulignant leur importance biologique et socio-culturelle. Dans un premier temps, nous expliquons la toponymie ou l’éponymie des grands fleuves des bassins refuges et de dispersion, à savoir les bassins de la Bemarivo, de l’Antainambalana, du Mangoro, de la Manampatrana, de la Mananara du Sud, du Mandrare, de l’Onilahy, du Mangoky, de la Tsiribihina, de la Betsiboka, de la Maevarano, du Sambirano et de la Mahavavy du Nord. Puis nous proposons une toponymie pour chacun des 17 centres et sous-centres d’endémisme en justifiant leurs particularités. Nous retenons ainsi les centres d’endémisme de Vohimarina, de l’Atsinanana (dont Masoala et Analanjirofo), Tanala, de Manombo, de l’Anosy, d’Ala maika (dont Ranopiso, Karimbola et Mikea), du Menabe, du Melaky, de la Sofia, d’Ampasindava, d’Ankify et de l’Ankarana. Nous illustrons chacun des centres d’endémisme avec une espèce symbolique et rapportons des aspects de son histoire naturelle et culturelle ainsi que de sa conservation

Pulsar Scintillation through Thick and Thin: Bow Shocks, Bubbles, and the Broader Interstellar Medium

Observations of pulsar scintillation are among the few astrophysical probes of very small-scale ($\lesssim$ au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and intensity distributions, can be related to interstellar turbulence and potentially over-pressurized plasma in local ISM inhomogeneities, such as supernova remnants, HII regions, and bow shocks. Here we present a survey of eight pulsars conducted at the Five-hundred-meter Aperture Spherical Telescope (FAST), revealing a diverse range of scintillation arc characteristics at high sensitivity. These observations reveal more arcs than measured previously for our sample. At least nine arcs are observed toward B1929$+$10 at screen distances spanning $\sim 90\%$ of the pulsar's $361$ pc path-length to the observer. Four arcs are observed toward B0355$+$54, with one arc yielding a screen distance as close as $\sim10^5$ au ($<1$ pc) from either the pulsar or the observer. Several pulsars show highly truncated, low-curvature arcs that may be attributable to scattering near the pulsar. The scattering screen constraints are synthesized with continuum maps of the local ISM and other well-characterized pulsar scintillation arcs, yielding a three-dimensional view of the scattering media in context.Comment: 20 pages, 14 figures. Submitted to MNRAS and comments welcome. Interactive version of Figure 12 available at https://stella-ocker.github.io/scattering_ism3d_ocker202

Pulsar scintillation through thick and thin: Bow shocks, bubbles, and the broader interstellar medium

Observations of pulsar scintillation are among the few astrophysical probes of very small-scale (≲ au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and intensity distributions, can be related to interstellar turbulence and potentially overpressurized plasma in local ISM inhomogeneities, such as supernova remnants, H II regions, and bow shocks. Here we present a survey of eight pulsars conducted at the Five-hundred-metre Aperture Spherical Telescope (FAST), revealing a diverse range of scintillation arc characteristics at high sensitivity. These observations reveal more arcs than measured previously for our sample. At least nine arcs are observed toward B1929+10 at screen distances spanning ~90 per cent of the pulsar’s 361 pc path length to the observer. Four arcs are observed toward B0355+54, with one arc yielding a screen distance as close as ∼105 au (<1 pc) from either the pulsar or the observer. Several pulsars show highly truncated, low-curvature arcs that may be attributable to scattering near the pulsar. The scattering screen constraints are synthesized with continuum maps of the local ISM and other well-characterized pulsar scintillation arcs, yielding a three-dimensional view of the scattering media in context