The Perseus spiral arm in the Anticenter direction

 

The thesis developed by Maria Monguió was just presented this November, 11/2013

The main purpose of her work is to map the radial variation of the stellar density for the young stellar population in the Galactic anticenter direction in order to understand the structure and location of the Perseus spiral arm. A Strömgren photometric survey covering 16 square degrees in the anticenter direction was carried out using the Wide Field Camera at the Isaac Newton Telescope. As a result, a main catalog of 35974 stars with all Strömgren indexes has been obtained, together with a extended one with 96980 stars with partial data. These large samples permit us to analyze the stellar surface density variation associated to the Perseus arm and to study the properties of the stellar component and the interstellar extinction in the anticenter direction. To compute the physical parameters for these stars two different approaches have been used, 1) the available pre-Hipparcos empirical calibrations based on cluster data and trigonometric parallaxes, and 2) a new model based method using atmospheric models and evolutionary tracks, optimized for stars up to Teff >7000K. Results for both of them have been compared with Hipparcos data looking for possible biases and trends. The obtained physical parameters allow us to select the intermediate young stars useful for our studies (B5-A3). These stars are young enough to still have a small intrinsic velocity dispersion (making them respond stronger to a perturbation), but they are also old enough to have approached a dynamic equilibrium with the spiral perturbation. Through their stellar distances, and after defining distance complete samples between 1.2 and 3 kpc, we can trace the density distribution in the anticenter direction, finding a clear overdensity around 1.7 kpc with an amplitude of 10% that can be associated to the Perseus arm. Exponential fittings also allowed us to constrain the radial scale length of the young population of the Galaxy, as well as to estimate the stellar density at the solar vicinity. In addition, all these data allow the creation of a 3D extinction map, that carefully analyzed shows the presence of a dust layer clearly in front of the location of the stellar overdensity of the arm, suggesting that the corotation radius of the spiral pattern is further away of the position of the Perseus arm.

 

resume writing service virginia beach quality essay service trigonometry homework help purchase a dissertation grant buy essay for college 247 online homework help order cheap calcium carbonate online order argumentative essay content writing services company free practice 11 plus papers online college board essay help best secure site to purchase serophene essay on birth order and achievement acheter zoloft sur lyon 64 homework help social issues cheat essay checker coumadin eye surgery homework help human resources does homework help statistics newt gingrich phd dissertation help with dissertation writing 4 a research paper custom essay writings doctoral dissertation help qualitative custom writings no plagiarism toilet paper machine for sale cape town cover letter for medical receptionist no experience help with essay plan dissertation buy uk admission essays services homework help questions answers need someone to write my business plan hindi essays websites buy paper bags online canada resume example for sales associate school papers for sale order of pages in a dissertation homework help in statistics learn to write an essay letter of recommendation writing service help writing scientific paper dissertation ionesco la lecon writing services ottawa hydrology homework help resume for medical assistant student high school history homework help homework help ads 24 7 pharmacy extra super lovevitra college admissions essay writing service styles of essays thesis on eating disorders custom essay club harcourt homework helper cover letter for merchandising job thesis statement for paper on bipolar disorder pima homework help dissertation student loan admission essay writing letter to a friend thesis sociology masters essays written about the metamorphosis speech writing helper how to write my name in arabic calligraphy personal statement writing service uk natrol vitamin buy college application essay jmu essays written by em forster ddavp refill from canada cover letter examples for sales associate position custom writing in 24 hrs homework help verbs anxiety disorder essay social purdue university admissions essay should they hire me essay best buy case study swot admission essay editing services yahoo answers admissions essay help i need help with my economics homework cheap resume writer dbq essay on louisiana purchase paper rewriting service purchase literature review graduate school personal statement writing service can you pay someone to write an essay buying school papers online reflective essay writing help best college application essay university of michigan buy a dissertation online search homework help engineering students proventil were to buy resume sample for sales manager buy a dissertation cheap recommendation letter for student admission essay cover page professional assignment writers essay on parents homework help word unscrambler help with cover letter and resume liv3 homework help business plan for buying an existing business uk buy custom research papers post traumatic stress disorder essays papers how to start a college admissions essay buy working papers online conclusion essay help help with writing papers cover letter multiple hiring managers paper pistol targets for sale monster resume help best cv writing service in dubai how to write a comparison essay essays written on the awakening by kate chopin 10mg cephalexin job order costing essay cheap essay for 10 dollars help writing a speech homework helpresearch paper study help online best resume writing services dc consumer reports sitekey buy essays cheap homework help lapl swot analysis of best buy thesis statement for comparing two songs 10 mg human growth agent for sale pennsylvania pa buy college application essay vs personal statement cheap essay writing service canada live homework help alaska very cheap dissertation writtig service order thesis oxford essay writing experts professional college application essay writers needed help with writing a dissertation 3 days pay someone to do essay pcci papers for sale free personal statement editing services autobiography of a yogi online purchase helper to do dissertation www dissertation helper co uk 50 mg tentex forte cheap thesis about guidance services estrace ohne rezept bestellen histrionic personality disorder case study pdf verizon free phone family plan cover letters for medical office administration executive resume writing service write my research paper for money religion homework help site listing temp to hire on resume master thesis opinion mining essay help facebook how to write my first cv evoque autobiography dynamic for sale help with mba essays writing services websites spatial order essay writing phd thesis on cement industry business plan writing services los angeles essay how to buy a used car how to get help online writing an essay custom essay online papers buy isoptin sr online in nz dissertation writing and depression professional resume writing service miami how to write a treatment plan for mental health buy discount Asacol online master thesis on english literature restaurant manager resume help eur rsm thesis get cheap eskalith no prescription best resume writing services in new york city 80s help with writing a dissertation construction students where can i write a paper online for free help with writting my term paper essay help introduction paragraph graduate thesis paper to purchase birth order essay introduction plans for a jewelry box essays written by sigmund freud buy book reviews on amazon no dissertation phd are there any legit essay writing services help on dissertation the canon and feudal law homework help for u cv and linkedin writing service belgian malinois pcci papers for sale case study anxiety disorders need someone to do my assignment purchase manager job description dissolution papers online best resume writing service nj singapore year 7 history homework help we buy paper cheap homework assignments where can i buy a research paper yahoo i need help writing my paper do my maths homework for me best essay writing services reviews philosophy essay help can a chiropractor help with spondylothesis master thesis in law 10 best resume writing services ga write my essay for me free purchase hamlet papper