The mysterious object around Mrk 1172

A nebular region with strong emission lines is found near the quiescent Early- Type Galaxy (ETG) Mrk 1172. Extensive studies are performed in order to de- termine the nature of this object, since to the best of our knowledge this object has not been analysed in detail before. The data used in this work is from the Multi Unit Spectroscopic Explorer (MUSE), at the Very Large Telescope (VLT) from the European Southern Observatory (ESO), covering the spectral range 4650 – 9300 ̊A. An analysis of the spatially resolved stellar populations of Mrk 1172 and its neighbour in projection (from now on we refer to the nebular region as BCD- UFRGS-01) reveals that while Mrk 1172 is dominated by old stellar populations with t ∼ 1010 yrs, BCD-UFRGS-01 presents two dominant stellar populations. The youngest of both, which has the lowest contribution (∼ 40 %), is composed of young stars with t ∼ 108 yrs, while the other has t ∼ 109 yrs. We determined the stellar mass of both objects, obtaining ∼ 2 × 1011 M for Mrk 1172 and ∼ 4 × 109 M for BCD-UFRGS-01. We also calculate a lower limit for the mass of the ionised gas in BCD-UFRGS-01, obtaining 3.5 × 106 M . The relative abundances of the ions associated with the emission lines present in the spectrum of BCD-UFRGS-01, i.e., N, S and O, are also determined. This calculation was performed for all spaxels of BCD-UFRGS-01, where we have obtained the average values of N(O++) = 7.71, N(N +) = 6.91 and N(S +) = 6.56, in units of log(X/H) + 12. The values obtained for Oxygen abundance (∼ 1/15Z ) and stellar mass are within the typical range of values found for other Blue Compact Dwarf Galaxies (BCDGs). The spectrum of BCD-UFRGS-01 shows very intense emission lines, namely [O iii] λ5007 ̊A, Hα, [N ii] λ6584 ̊A, and [Sii] λ6717 ̊A . From such emission line ratios we concluded that the gas within BCD-UFRGS-01 is ionised by young massive stars. Measurements of SFR and PSFR result in 0.71 M yrs−1 and 1.4× 10−2 M yrs−1 kpc−2 , respectively. Dynamical analysis of this galaxy reveals that the gas is rotating in the counter- clockwise direction along a major axis that crosses BCD-UFRGS-01 diagonally, and its motion is compatible with the motion of circular orbits in the plane of a disk. Thus, we conclude that BCD-UFRGS-01 is likely to be a dwarf disc galaxy that belongs to the Blue Compact Dwarf Galaxy Category.Uma região nebular com fortes linhas de emissão foi encontrada próxima à galáxia elíptica e quiescente Mrk 1172. Estudos extensivos foram realizados com o intuito de determinar a natureza desse objeto, uma vez que, até onde sabemos, não existem estudos prévios sobre este objeto na literatura. Os dados utilizados nesse trabalho são provenientes do espectrógrafo Multi Unit Spectroscopic Explorer (MUSE), no Very Large Telescope (VLT) do European Southern Observatory (ESO), cobrindo o intervalo em comprimento de onda de 4650 – 9300 ̊A. Um estudo espacialmente resolvido das populações estelares dominantes em cada sistema (chamamos este ob jeto de BCD-UFRGS-01) revela que, enquanto Mrk 1172 é dominada por populações estelares velhas com t ∼ 1010 anos, BCD-UFRGS-01 apresenta duas populações estelares dominantes. A mais jovem delas, que possui menor contribuição (∼ 40 %), é composta por estrelas jovens com idades ∼ 108 anos, enquanto a outra possui idade da ordem de 109 anos. Determinamos a massa estelar de ambas, obtendo ∼ 2 ×1011 M para Mrk 1172 e ∼ 4 ×109 M para BCD-UFRGS-01. Calculamos também o limite inferior da massa do gás ionizado em BCD-UFRGS-01, obtendo 3.5 ×106 M . As abundâncias relativas dos ions associados ás linhas de emissão presentes no espectro de BCD-UFRGS-01, i.e., N, S e O, também foram determinadas. Esse cálculo foi reproduzido para todos os spaxels de BCD-UFRGS-01, onde obtivemos uma média de N(O++) = 7.71, N(N +) = 6.91 e N(S +) = 6.56, em unidades de log(X/H) + 12. Os valores de abundância de oxigênio (∼ 1/15Z ) e massa estelar obtidos estão dentro do intervalo tíıpico encontrado para Blue Compact Dwarf Galaxies (BCDGs). O espectro de BCD-UFRGS-01 apresenta linhas de emissão muito intensas, como [O iii] λ5007 ̊A, Hα, [N ii] λ6584 ̊A, and [Sii] λ6717 ̊A . A partir da razão dessas linhas concluímos que o gás de BCD-UFRGS-01 é ionizado por estrelas jovens massivas. Medidas de SFR e PSFR resultam em 0.71 M anos−1 e 1.4 × 10−2 M anos−1 kpc−2 , respectivamente. Estudos da dinâmica deste objeto revelam também que o gás está rotando no sentido anti-horário em torno de um eixo maior de BCD-UFRGS-01 e seu movimento é compatível com o movimento de órbita circular no plano de um disco. Concluíımos, portanto, que BCD-UFRGS-01 é uma galáxia anã discoidal e é uma forte candidata a se encaixar na categoria de Blue Compact Dwarf Galaxy

The metal-poor dwarf irregular galaxy candidate next to Mrk 1172

In this work, we characterize the properties of the object SDSS J020536.84−081424.7, an extended nebular region with projected extension of 14 × 14 kpc2 in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 (1 × 1011 M ) and our object of study (3 × 109 M ). While the stellar content of Mrk 1172 is dominated by an old (∼10 Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from ∼100 Myr to ∼1 Gyr) and presents strong emission lines such as H β; [O III] λλ4959, 5007 Å; H α; [N II] λλ6549, 6585 Å; and [S II] λλ6717, 6732 Å. Using these emission lines, we find that it is metal poor (with Z ∼ 1/3 Z , comparable to the LMC) and is actively forming stars (0.70 M yr−1), especially in a few bright clumpy knots that are readily visible in H α. The object has an ionized gas mass ≥3.8 × 105 M . Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disc and is being affected by interaction wtih Mrk 1172. We conclude that SDSS J020536.84−081424.7 is most likely a dwarf irregular galaxy (the dIGal)

The mysterious object around Mrk 1172

A nebular region with strong emission lines is found near the quiescent Early- Type Galaxy (ETG) Mrk 1172. Extensive studies are performed in order to de- termine the nature of this object, since to the best of our knowledge this object has not been analysed in detail before. The data used in this work is from the Multi Unit Spectroscopic Explorer (MUSE), at the Very Large Telescope (VLT) from the European Southern Observatory (ESO), covering the spectral range 4650 – 9300 ̊A. An analysis of the spatially resolved stellar populations of Mrk 1172 and its neighbour in projection (from now on we refer to the nebular region as BCD- UFRGS-01) reveals that while Mrk 1172 is dominated by old stellar populations with t ∼ 1010 yrs, BCD-UFRGS-01 presents two dominant stellar populations. The youngest of both, which has the lowest contribution (∼ 40 %), is composed of young stars with t ∼ 108 yrs, while the other has t ∼ 109 yrs. We determined the stellar mass of both objects, obtaining ∼ 2 × 1011 M for Mrk 1172 and ∼ 4 × 109 M for BCD-UFRGS-01. We also calculate a lower limit for the mass of the ionised gas in BCD-UFRGS-01, obtaining 3.5 × 106 M . The relative abundances of the ions associated with the emission lines present in the spectrum of BCD-UFRGS-01, i.e., N, S and O, are also determined. This calculation was performed for all spaxels of BCD-UFRGS-01, where we have obtained the average values of N(O++) = 7.71, N(N +) = 6.91 and N(S +) = 6.56, in units of log(X/H) + 12. The values obtained for Oxygen abundance (∼ 1/15Z ) and stellar mass are within the typical range of values found for other Blue Compact Dwarf Galaxies (BCDGs). The spectrum of BCD-UFRGS-01 shows very intense emission lines, namely [O iii] λ5007 ̊A, Hα, [N ii] λ6584 ̊A, and [Sii] λ6717 ̊A . From such emission line ratios we concluded that the gas within BCD-UFRGS-01 is ionised by young massive stars. Measurements of SFR and PSFR result in 0.71 M yrs−1 and 1.4× 10−2 M yrs−1 kpc−2 , respectively. Dynamical analysis of this galaxy reveals that the gas is rotating in the counter- clockwise direction along a major axis that crosses BCD-UFRGS-01 diagonally, and its motion is compatible with the motion of circular orbits in the plane of a disk. Thus, we conclude that BCD-UFRGS-01 is likely to be a dwarf disc galaxy that belongs to the Blue Compact Dwarf Galaxy Category.Uma região nebular com fortes linhas de emissão foi encontrada próxima à galáxia elíptica e quiescente Mrk 1172. Estudos extensivos foram realizados com o intuito de determinar a natureza desse objeto, uma vez que, até onde sabemos, não existem estudos prévios sobre este objeto na literatura. Os dados utilizados nesse trabalho são provenientes do espectrógrafo Multi Unit Spectroscopic Explorer (MUSE), no Very Large Telescope (VLT) do European Southern Observatory (ESO), cobrindo o intervalo em comprimento de onda de 4650 – 9300 ̊A. Um estudo espacialmente resolvido das populações estelares dominantes em cada sistema (chamamos este ob jeto de BCD-UFRGS-01) revela que, enquanto Mrk 1172 é dominada por populações estelares velhas com t ∼ 1010 anos, BCD-UFRGS-01 apresenta duas populações estelares dominantes. A mais jovem delas, que possui menor contribuição (∼ 40 %), é composta por estrelas jovens com idades ∼ 108 anos, enquanto a outra possui idade da ordem de 109 anos. Determinamos a massa estelar de ambas, obtendo ∼ 2 ×1011 M para Mrk 1172 e ∼ 4 ×109 M para BCD-UFRGS-01. Calculamos também o limite inferior da massa do gás ionizado em BCD-UFRGS-01, obtendo 3.5 ×106 M . As abundâncias relativas dos ions associados ás linhas de emissão presentes no espectro de BCD-UFRGS-01, i.e., N, S e O, também foram determinadas. Esse cálculo foi reproduzido para todos os spaxels de BCD-UFRGS-01, onde obtivemos uma média de N(O++) = 7.71, N(N +) = 6.91 e N(S +) = 6.56, em unidades de log(X/H) + 12. Os valores de abundância de oxigênio (∼ 1/15Z ) e massa estelar obtidos estão dentro do intervalo tíıpico encontrado para Blue Compact Dwarf Galaxies (BCDGs). O espectro de BCD-UFRGS-01 apresenta linhas de emissão muito intensas, como [O iii] λ5007 ̊A, Hα, [N ii] λ6584 ̊A, and [Sii] λ6717 ̊A . A partir da razão dessas linhas concluímos que o gás de BCD-UFRGS-01 é ionizado por estrelas jovens massivas. Medidas de SFR e PSFR resultam em 0.71 M anos−1 e 1.4 × 10−2 M anos−1 kpc−2 , respectivamente. Estudos da dinâmica deste objeto revelam também que o gás está rotando no sentido anti-horário em torno de um eixo maior de BCD-UFRGS-01 e seu movimento é compatível com o movimento de órbita circular no plano de um disco. Concluíımos, portanto, que BCD-UFRGS-01 é uma galáxia anã discoidal e é uma forte candidata a se encaixar na categoria de Blue Compact Dwarf Galaxy

Diminishing benefits of urban living for children and adolescents’ growth and development

Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified