[:en][three_fourth last=\u00bbno\u00bb spacing=\u00bbyes\u00bb center_content=\u00bbno\u00bb hide_on_mobile=\u00bbno\u00bb background_color=\u00bb\u00bb background_image=\u00bb\u00bb background_repeat=\u00bbno-repeat\u00bb background_position=\u00bbleft top\u00bb hover_type=\u00bbnone\u00bb link=\u00bb\u00bb border_position=\u00bball\u00bb border_size=\u00bb0px\u00bb border_color=\u00bb\u00bb border_style=\u00bb\u00bb padding=\u00bb\u00bb margin_top=\u00bb\u00bb margin_bottom=\u00bb\u00bb animation_type=\u00bb\u00bb animation_direction=\u00bb\u00bb animation_speed=\u00bb0.1″ animation_offset=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][fusion_text]<\/p>\n
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The Universe is bursting of galaxies with many shapes and sizes. What kind is ours? Trying to infer the morphology of the Milky Way is not a simple thing to do. We live inside it, and we can’t just go on a trip outside of it and take a picture because the distances involved are very long and an interstellar voyage of this kind would take thousands of millions of years. Our only option is to rely in our ingenuity.<\/strong><\/p>\n Two centuries ago, the German astronomer, William Herschel, put the first piece of the jigsaw.<\/strong> By counting stars in several directions, he concluded that we live in the inner part of a flattened and irregular stellar system. Even though the general idea is correct, he missed two points. He neither knew that the interstellar environment is full of dust that blocks the starlight, so that the furthest stars remain unseen, nor he knew a reliable method to estimate how far the stars were.<\/p>\n Measuring the distance of the stars is challenging but not impossible.<\/strong> The first thing that someone might think is that the stars that seem dim are farther away and the brighter ones are closer. This concept would be right if the stars were all the same and this is exactly what Herschel assumed in his calculation. But reality is far from that. Stars come in different colors and brightness, which means that is quite difficult to tell whether a luminous dot in the sky comes from a bright star far away or a dim star nearby. This is similar to the impossibility of distinguishing between a flashlight beam coming from a boat on the seashore and a huge lighthouse a few kilometers away. Luckily for astronomers, several methods to measure stellar distances have been discovered, and one of them is provided by pulsating stars, one of the types of stars that display periodical change in brightness. Nowadays, we know measuring the time that a pulsating star takes to light up and down is enough to estimate its distance.<\/strong><\/p>\n There is also a trick to observe through the dust. Although the visible light that stars produce cannot pass through the thick \u201csmog\u201d curtains that tore us apart, stars also emit other types of electromagnetic radiation that are able to reach us. The infrared radiation is an example of this kind of \u201cmagic\u201d light and, although our eyes cannot see it our cutting-edge telescopes do.<\/p>\n Thus, thanks to the ability to observe through the dust and to compute distances, we have developed the current idea of what our galaxy is. We live in a disk-shaped stellar system with a protuberance in the center, called Bulge. So, if you take 2 pan fried eggs and stick them together back to back (on the flat sides) the resulting object would have, basically, the shape of the Milky Way. We are living in the \u201cwhite\u201d zone, 27.000 light years away from the center of the \u201cyolk\u201d.<\/strong><\/p>\n In the \u201990s, it was suggested that the galactic \u201cyolk\u201d had instead the shape of a bar viewed side on, and this was actually confirmed by the Spitzer infrared space telescope in 2005. Recently, we discovered that this bar is indeed the result of two components, one with the shape of a peanut and the other with the shape of a sphere. Thus, new discoveries about the morphology of our galaxy follow one another thanks to even more detailed studies.<\/p>\n We wanted to take on the challenge of studying the Milky Way\u2019s most difficult access region, its heart.<\/strong> Since 2010, the project Vista variables in the Via Lactea (https:\/\/en.wikipedia.org\/wiki\/Vista_Variables_in_the_Via_Lactea) has been using the VISTA telescope, located at Cerro Paranal, to observe the infrared radiation that millions of stars located near the galactic center -and in part of the galactic disk too- emit. Our work consisted in comparing all the images of the inner area with the aim of detecting stars showing variations in their brightness. Our interest has been mainly focused on identifying a very special type of pulsating star called RR Lyrae<\/strong> (RRL). RRL stand out because they are considered one of the oldest stars in our Universe and finding them means that we have real witnesses of the Galaxy nucleus formation process.<\/p>\n Therefore, in 2016 (https:\/\/www.eso.org\/public\/news\/eso1636\/) and after months of working, we were able to detect for the first time this kind of variable stars, 27.000 light years away from us, located thus in the very center of the Galaxy.<\/strong> Their mere presence tells us that this region could have formed at least 10.000 million years ago since this is the minimum age estimated for RRL stars. During 2018, we have extended the searching area and not only we have found more RRL but also the comparison between images has allowed us to study their movements across the space. Our main result (http:\/\/adsabs.harvard.edu\/abs\/2018ApJ…863…79C) was that the oldest fossils of our Galaxy, represented by the RRL population, move around the galactic Bulge as a swarm of bees and they did not show any evidence of being rotating, as an ensemble, around this center. This fact might be suggesting that the inner and oldest component of the Bulge was born due to the gravitational collapse of a gas cloud formed shortly after the Big Bang.<\/p>\n Amongst the thousands of millions of galaxies that we are able to observe the Milky Way is special not only because we are living inside it, but also due to the detailed studies we can carry out. This means that new discoveries about its shape and history are around the corner, and I am sure that our team will devotedly and excitedly keep working to find more clues that might help us to better understand when and how the heart of the Milky Way did start to beat.<\/strong><\/p>\n Main image: The center of the Milky Way as seen in infrared light[\/fusion_text][\/three_fourth][one_fourth last=\u00bbyes\u00bb spacing=\u00bbyes\u00bb center_content=\u00bbno\u00bb hide_on_mobile=\u00bbno\u00bb background_color=\u00bb\u00bb background_image=\u00bb\u00bb background_repeat=\u00bbno-repeat\u00bb background_position=\u00bbleft top\u00bb hover_type=\u00bbnone\u00bb link=\u00bb\u00bb border_position=\u00bball\u00bb border_size=\u00bb0px\u00bb border_color=\u00bb\u00bb border_style=\u00bb\u00bb padding=\u00bb\u00bb margin_top=\u00bb\u00bb margin_bottom=\u00bb\u00bb animation_type=\u00bb\u00bb animation_direction=\u00bb\u00bb animation_speed=\u00bb0.1″ animation_offset=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][testimonials design=\u00bbclassic\u00bb backgroundcolor=\u00bb\u00bb textcolor=\u00bb\u00bb random=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][testimonial name=\u00bbBy Rodrigo Contreras Ramos, MAS postdoctoral researcher\u00bb avatar=\u00bbnone\u00bb image=\u00bb\u00bb image_border_radius=\u00bb\u00bb company=\u00bb\u00bb link=\u00bb\u00bb target=\u00bb_self\u00bb]\u00bbTrying to infer the morphology of the Milky Way is not a simple thing to do. We live inside it, and we can’t just go on a trip outside of it and take a picture because the distances involved are very long and an interstellar voyage of this kind would take thousands of millions of years. Our only option is to rely in our ingenuity.\u00bb[\/testimonial][\/testimonials][\/one_fourth][fusion_text]<\/p>\n [\/fusion_text][:es][three_fourth last=\u00bbno\u00bb spacing=\u00bbyes\u00bb center_content=\u00bbno\u00bb hide_on_mobile=\u00bbno\u00bb background_color=\u00bb\u00bb background_image=\u00bb\u00bb background_repeat=\u00bbno-repeat\u00bb background_position=\u00bbleft top\u00bb hover_type=\u00bbnone\u00bb link=\u00bb\u00bb border_position=\u00bball\u00bb border_size=\u00bb0px\u00bb border_color=\u00bb\u00bb border_style=\u00bb\u00bb padding=\u00bb\u00bb margin_top=\u00bb\u00bb margin_bottom=\u00bb\u00bb animation_type=\u00bb\u00bb animation_direction=\u00bb\u00bb animation_speed=\u00bb0.1″ animation_offset=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][fusion_text]<\/p>\n <\/p>\n El Universo est\u00e1 lleno de galaxias de distintas formas y tama\u00f1os \u00bfDe qu\u00e9 tipo es la nuestra? Descifrar la morfolog\u00eda de la V\u00eda L\u00e1ctea no es tarea nada de f\u00e1cil. Vivimos inmersos en ella y no podemos viajar para tomar una selfie<\/em> desde afuera, pues las distancias involucradas son demasiado grandes y tardar\u00edamos miles de millones de a\u00f1os en una traves\u00eda interestelar de este tipo. No nos queda otra que usar el ingenio.<\/strong><\/p>\n Dos siglos atr\u00e1s, el astr\u00f3nomo alem\u00e1n William Herschel puso la primera pieza del puzzle<\/strong>. Simplemente contando estrellas en direcciones diferentes, Herschel concluy\u00f3 que viv\u00edamos al interior de un sistema estelar aplanado e irregular. Si bien la idea general es correcta, hab\u00eda dos puntos que no consider\u00f3. \u00c9l no sab\u00eda que en el medio interestelar existe una gran cantidad de polvo que bloquea la luz de las estrellas impidiendo ver las que se encuentran m\u00e1s lejanas. Por otro lado, tampoco conoc\u00eda un m\u00e9todo preciso para estimar que tan lejos se encontraban las estrellas.<\/p>\n El problema de medir la distancia a las estrellas es complicado de resolver, pero no imposible<\/strong>. Lo primero que uno tender\u00eda a pensar, es que las estrellas que se ven d\u00e9biles est\u00e1n lejos, y las que aparecen brillantes est\u00e1n m\u00e1s cerca. Esto ser\u00eda cierto si todas las estrellas fueran iguales y es justamente lo que Herschel asumi\u00f3 en su c\u00e1lculo, pero la realidad es muy distinta. Existen estrellas de diferentes brillos y colores y esto quiere decir que no es posible distinguir si un punto luminoso en el cielo proviene de una estrella brillante lejana o de una estrella d\u00e9bil cercana, al igual que no es posible distinguir la luz de una linterna que proviene de un bote a la orilla de la playa o de un enorme faro a algunos kil\u00f3metros de distancia.<\/p>\n Afortunadamente para los astr\u00f3nomos, se han encontrado variados m\u00e9todos para deducir distancias estelares y uno de ellos lo proveen las estrellas pulsantes, uno de los tipos de estrellas que var\u00edan su brillo peri\u00f3dicamente. Hoy sabemos que basta simplemente medir el tiempo que demora una estrella variable pulsante en \u00abprenderse y apagarse\u00bb para estimar su distancia.<\/strong><\/p>\n Tambi\u00e9n existe un truco para mirar a trav\u00e9s del polvo. Si bien la luz visible que emiten las estrellas no es capaz de atravesar las espesas cortinas de \u00absmog\u00bb que nos separan, otros tipos de radiaci\u00f3n electromagn\u00e9tica provenientes de ellas si logran llegar hasta nosotros. La radiaci\u00f3n infrarroja es un ejemplo de este tipo de luz \u00abm\u00e1gica\u00bb y aunque nuestros ojos son completamente ciegos a ella, no lo son nuestros modernos telescopios.<\/p>\n As\u00ed, gracias a la capacidad de observar a trav\u00e9s del polvo y de calcular distancias hemos podido hacernos la idea actual de lo que es nuestra galaxia. Vivimos en un sistema estelar que tiene forma de disco con una protuberancia al centro llamado Bulbo. Toma 2 huevos fritos y \u00fanelos por la parte de abajo, espalda con espalda: el objeto resultante tendr\u00e1, b\u00e1sicamente, la forma de la V\u00eda L\u00e1ctea. Nosotros vivimos en la \u00abclara\u00bb, a unos 27.000 a\u00f1os luz del centro de la \u00abyema\u00bb. <\/strong><\/p>\n En los a\u00f1os 90 se especul\u00f3 que la \u00abyema\u00bb gal\u00e1ctica ten\u00eda m\u00e1s bien la forma de una barra vista de perfil y esto se confirm\u00f3 con el telescopio espacial infrarrojo Spitzer en el a\u00f1o 2005. Recientemente descubrimos que la barra es en realidad la suma de dos componentes, una con forma de man\u00ed y otra con forma de esfera. As\u00ed, nuevos descubrimientos sobre la morfolog\u00eda de nuestra galaxia se suceden gracias a estudios cada vez m\u00e1s detallados.<\/p>\n Nosotros quisimos tomar el desaf\u00edo de estudiar la regi\u00f3n de la V\u00eda L\u00e1ctea de m\u00e1s dif\u00edcil acceso, su coraz\u00f3n<\/strong>. Desde el a\u00f1o 2010 que el proyecto Vista Variables in the V\u00eda L\u00e1ctea <\/em> (https:\/\/en.wikipedia.org\/wiki\/Vista_Variables_in_the_Via_Lactea<\/a>) ha estado utilizando el telescopio VISTA, ubicado en Cerro Paranal, para observar la radiaci\u00f3n infrarroja emitida por millones de estrellas que se ubican en direcci\u00f3n del centro gal\u00e1ctico (y un poco del disco gal\u00e1ctico tambi\u00e9n). Nuestro trabajo ha consistido en comparar todas las im\u00e1genes obtenidas de la zona m\u00e1s interna con el fin de detectar las estrellas que muestran variaci\u00f3n en su brillo. Nuestro inter\u00e9s ha estado especialmente dirigido en identificar un tipo muy especial de estrellas pulsantes llamadas RR Lyrae (RRL)<\/strong>. La particularidad de las RRL reside en que son consideradas entre las estrellas m\u00e1s antiguas del Universo y encontrarlas implica contar con verdaderos testigos del proceso de formaci\u00f3n del n\u00facleo de la galaxia.<\/p>\n As\u00ed, en 2016 (<\/strong>https:\/\/www.eso.org\/public\/news\/eso1636\/<\/strong><\/a>) y luego de meses de trabajo, hemos podido detectar por primera vez este tipo de estrellas variables a 27.000 a\u00f1os luz de nosotros, o sea en el centro mismo de la Galaxia.<\/strong> Su mera presencia nos indica que esta regi\u00f3n tiene que haber empezado a formarse al menos hace 10 mil millones de a\u00f1os, pues esa es la edad m\u00ednima estimada de las RRL. Durante el 2018, hemos aumentado el \u00e1rea de b\u00fasqueda y no solo hemos podido encontrar nuevas RRL, sino que la comparaci\u00f3n de im\u00e1genes tambi\u00e9n nos ha permitido estudiar sus movimientos en el espacio. El resultado que hemos encontrado (http:\/\/adsabs.harvard.edu\/abs\/2018ApJ…863…79C<\/a>) ha sido que los f\u00f3siles m\u00e1s antiguos de nuestra galaxia, representados por las RRL, se mueven como un enjambre de abejas alrededor del n\u00facleo gal\u00e1ctico y no muestran evidencia de estar rotando, en forma conjunta, en torno a este centro. Esto nos podr\u00eda estar diciendo que la componente m\u00e1s vieja e interna del Bulbo naci\u00f3 debido al colapso gravitacional de una nube de gas formada poco despu\u00e9s del Big Bang.<\/p>\n De las miles de millones de galaxias que podemos observar, la nuestra es especial no solo porque vivimos en ella sino que tambi\u00e9n porque la podemos estudiar con incre\u00edble detalle. Esto significa que nuevos descubrimientos est\u00e1n por venir sobre su forma e historia y tengo la certeza que nuestro grupo seguir\u00e1 trabajando con dedicaci\u00f3n y entusiasmo para encontrar m\u00e1s pistas que nos ayuden a entender mejor cu\u00e1ndo y c\u00f3mo comenz\u00f3 a latir el coraz\u00f3n de la V\u00eda L\u00e1ctea. <\/strong><\/p>\n Imagen principal: Visi\u00f3n del centro de la V\u00eda L\u00e1ctea en luz infrarroja[\/fusion_text][\/three_fourth][one_fourth last=\u00bbyes\u00bb spacing=\u00bbyes\u00bb center_content=\u00bbno\u00bb hide_on_mobile=\u00bbno\u00bb background_color=\u00bb\u00bb background_image=\u00bb\u00bb background_repeat=\u00bbno-repeat\u00bb background_position=\u00bbleft top\u00bb hover_type=\u00bbnone\u00bb link=\u00bb\u00bb border_position=\u00bball\u00bb border_size=\u00bb0px\u00bb border_color=\u00bb\u00bb border_style=\u00bb\u00bb padding=\u00bb\u00bb margin_top=\u00bb\u00bb margin_bottom=\u00bb\u00bb animation_type=\u00bb\u00bb animation_direction=\u00bb\u00bb animation_speed=\u00bb0.1″ animation_offset=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][testimonials design=\u00bbclassic\u00bb backgroundcolor=\u00bb\u00bb textcolor=\u00bb\u00bb random=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][testimonial name=\u00bbPor Rodrigo Contreras Ramos, investigador postdoctoral del MAS\u00bb avatar=\u00bbnone\u00bb image=\u00bb\u00bb image_border_radius=\u00bb\u00bb company=\u00bb\u00bb link=\u00bb\u00bb target=\u00bb_self\u00bb]\u00bbDescifrar la morfolog\u00eda de la V\u00eda L\u00e1ctea no es tarea nada de f\u00e1cil. Vivimos inmersos en ella y no podemos viajar para tomar una selfie desde afuera, pues las distancias involucradas son demasiado grandes y tardar\u00edamos miles de millones de a\u00f1os en una traves\u00eda interestelar de este tipo. No nos queda otra que usar el ingenio\u00bb[\/testimonial][\/testimonials][\/one_fourth][fusion_text]<\/p>\n [\/fusion_text][:]<\/p>","protected":false},"excerpt":{"rendered":" [:en][three_fourth last=\u00bbno\u00bb spacing=\u00bbyes\u00bb center_content=\u00bbno\u00bb hide_on_mobile=\u00bbno\u00bb background_color=\u00bb\u00bb background_image=\u00bb\u00bb background_repeat=\u00bbno-repeat\u00bb background_position=\u00bbleft top\u00bb hover_type=\u00bbnone\u00bb link=\u00bb\u00bb border_position=\u00bball\u00bb border_size=\u00bb0px\u00bb border_color=\u00bb\u00bb border_style=\u00bb\u00bb padding=\u00bb\u00bb margin_top=\u00bb\u00bb margin_bottom=\u00bb\u00bb animation_type=\u00bb\u00bb animation_direction=\u00bb\u00bb animation_speed=\u00bb0.1″ animation_offset=\u00bb\u00bb class=\u00bb\u00bb id=\u00bb\u00bb][fusion_text] By Rodrigo Contreras Ramos, MAS postdoctoral researcher<\/p>","protected":false},"author":5,"featured_media":27609,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_eb_attr":"","footnotes":""},"categories":[59],"tags":[],"class_list":["post-18805","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-columnas"],"yoast_head":"\nPor Rodrigo Contreras Ramos, investigador postdoctoral MAS<\/strong><\/em><\/h4>\n