Tanveer Karim

University of Toronto | U of T · Astronomy

Measuring the growth of structure is a powerful probe for studying the dark sector, especially in light of the $\sigma_8$ tension between primary CMB anisotropy and low-redshift surveys. This paper provides a new measurement of the amplitude of the matter power spectrum, $\sigma_8$, using galaxy-galaxy and galaxy-CMB lensing power spectra of Dark E...

The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data...

We present the technical details on how large-scale structure (LSS) catalogs are constructed from redshifts measured from spectra observed by the Dark Energy Spectroscopic Instrument (DESI). The LSS catalogs provide the information needed to determine the relative number density of DESI tracers as a function of redshift and celestial coordinates an...

One important source of systematics in galaxy redshift surveys comes from the estimation of the galaxy window function. Up until now, the impact of the uncertainty in estimating the galaxy window function on parameter inference has not been properly studied. In this paper, we show that the uncertainty and the bias in estimating the galaxy window fu...

The Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubi...

The Dark Energy Spectroscopic Instrument (DESI) completed its five-month Survey Validation in May 2021. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate da...

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg$^2$ over five years to constrain the cosmic expansion history through precise measurements of Baryon Acoustic Oscillations (BAO). The scientific program for DESI was evaluated during a five month Survey Validation (SV) campaign before beginning full...

One important source of systematics in galaxy redshift surveys comes from the estimation of the galaxy window function. Up until now, the impact of the uncertainty in estimating the galaxy window function on parameter inference has not been properly studied. In this paper, we show that the uncertainty and the bias in estimating the galaxy window fu...

The Dark Energy Spectroscopic Instrument (DESI) will precisely constrain cosmic expansion and the growth of structure by collecting ∼40 million extragalactic redshifts across ∼80% of cosmic history and one-third of the sky. The Emission Line galaxy (ELG) sample, which will comprise about one-third of all DESI tracers, will be used to probe the univ...

In 2021 May, the Dark Energy Spectroscopic Instrument (DESI) began a 5 yr survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are emission line galaxies, luminous red galaxies, and quasars. In bright time, DESI will focus on two surveys known as the Bright Galaxy Survey and the Milky Way S...

The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond reds...

The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond reds...

In May, 2021, the Dark Energy Spectroscopic Instrument (DESI) began a five-year survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are Emission Line Galaxies (ELGs), Luminous Red Galaxies (LRGs) and quasars (QSOs). In bright time, DESI will focus on two surveys known as the Bright Galaxy...

The Dark Energy Spectroscopic Instrument (DESI) will precisely constrain cosmic expansion and the growth of structure by collecting $\sim$40 million extra-galactic redshifts across $\sim$80\% of cosmic history and one third of the sky. The Emission Line Galaxy (ELG) sample, which will comprise about one-third of all DESI tracers, will be used to pr...

The Galactic Centre is surrounded by two giant plasma lobes known as the Fermi bubbles, extending ~10 kpc both above and below the Galactic plane. Spectroscopic observations of Fermi bubble directions at radio, ultraviolet and optical wavelengths have detected multi-phase gas clouds thought to be embedded within the bubbles, referred to as Fermi bu...

The Galactic Center is surrounded by two giant plasma lobes known as the Fermi Bubbles, extending ~10 kpc both above and below the Galactic plane. Spectroscopic observations of Fermi Bubble directions at radio, ultraviolet, and optical wavelengths have detected multi-phase gas clouds thought to be embedded within the bubbles referred to as Fermi Bu...

The Dark Energy Spectroscopic Instrument (DESI) has embarked on an ambitious five-year survey to explore the nature of dark energy with spectroscopy of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the Baryon Acoustic Oscillation method to measure distances from the nearby universe to z > 3.5, as well as measure...

DESI will precisely constrain cosmic expansion and the growth of structure by collecting $\sim$35 million redshifts across $\sim$80% of cosmic history and one third of the sky to study Baryon Acoustic Oscillations (BAO) and Redshift Space Distortions (RSD). We present a preliminary target selection for an Emission Line Galaxy (ELG) sample, which wi...

DESI will precisely constrain cosmic expansion and the growth of structure by collecting ∼35 million redshifts across ∼80% of cosmic history and one third of the sky to study Baryon Acoustic Oscillations (BAO) and Redshift Space Distortions (RSD). We present a preliminary target selection for an Emission Line Galaxy (ELG) sample, which will compris...

The forthcoming Dark Energy Spectroscopic Instrument (DESI) experiment plans to measure the effects of dark energy on the expansion of the Universe and create a 3D map of the Universe using galaxies up to z ∼ 1.6 and QSOs up to z ∼ 3.5. In order to create this map, DESI will obtain spectroscopic redshifts of over 30 million objects; among them, a m...

Using new ultraviolet (UV) spectra of five background quasars from the Cosmic Origins Spectrograph on the Hubble Space Telescope, we analyze the low-latitude ( ) regions of the Fermi Bubbles, the giant gamma-ray-emitting lobes at the Galactic Center. We combine these data with previous UV and atomic hydrogen (H i ) data sets to build a comprehensiv...

The forthcoming Dark Energy Spectroscopic Instrument (DESI) experiment plans to measure the effects of dark energy on the expansion of the Universe and create a $3$D map of the Universe using galaxies up to $z \sim 1.6$ and QSOs up to $z \sim 3.5$. In order to create this map, DESI will obtain spectroscopic redshifts of over $30$ million objects; a...

Using new ultraviolet (UV) spectra of five background quasars from the Cosmic Origins Spectrograph on the Hubble Space Telescope, we analyze the low-latitude (|b|=20-30 degree) regions of the Fermi Bubbles, the giant gamma-ray emitting lobes at the Galactic Center. We combine these data with previous UV and atomic hydrogen (HI) datasets to build a...

Two giant plasma lobes, known as the Fermi Bubbles, extend 10 kpc above and below the Galactic Center. Since their discovery in X-rays in 2003 (and in gamma-rays in 2010), the Bubbles have been recognized as a new morphological feature of our Galaxy and a striking example of energetic feedback from the nuclear region. They remain the subject of int...

The Fermi Bubbles are two giant gamma-ray emitting lobes extending 55° above and below the Galactic center. While the Northern Bubble has been extensively studied in ultraviolet (UV) absorption, little is known about the gas kinematics of the southern Bubble. We use UV absorption-line spectra from the Cosmic Origins Spectrograph (COS) on the Hubble...

The Fermi Bubbles are two giant gamma-ray emitting lobes extending 55 deg above and below the Galactic Center. While the Northern Bubble has been extensively studied in ultraviolet (UV) absorption, little is known about the gas kinematics of the southern Bubble. We use UV absorption-line spectra from the Cosmic Origins Spectrograph (COS) on the Hub...

The Fermi Bubbles are two giant gamma-ray emitting lobes extending 55$^{\circ}$ above and below the Galactic Center. While the Northern Bubble has been extensively studied in ultraviolet (UV) absorption, little is known about the gas kinematics of the southern Bubble. We use UV absorption-line spectra from the Cosmic Origins Spectrograph (COS) on t...

The Fermi Bubbles are two giant lobes of plasma situated at the center of the Milky Way, extending 55° above and below the Galactic Midplane. Although the Bubbles have been widely studied in multiple wavelengths, few studies have been done in UV absorption. Here we present a statistical study of the Southern Fermi Bubble using 17 QSO sightlines — 6...

Science and Technology (S&T) research has become increasingly global in the twentieth and twenty-first centuries. However, the United States (US) and Russia, traditionally strong in the hard sciences, demonstrate less collaboration than expected in these areas. Blending interviews and data from the Thomson Reuters Incites Database, we conduct an an...

Magnetic cataclysmic variable stars have brightness variations that repeat with each revolution of the two stars about the center of mass of the system. However, in the case of QQ Vulpecula (QQ Vul), this brightness variation pattern changes in the long term. This study makes use of two decades worth of data from the Roboscope Telescope as well as...

The Fermi Bubbles are two giant gamma-ray emitting lobes, extending 55° below and above the Galactic Center, that were discovered in 2010. While the Northern Bubble has been extensively studied in ultraviolet (UV) absorption, little is known about the UV properties of the Southern Bubble. We use UV absorption-line spectra from the Hubble Space Tele...

Astronomers are entering an era of {\mu}as-level astrometry utilizing the 5-decade-old IAU Galactic coordinate system that was only originally defined to $\sim$0{\deg}.1 accuracy, and where the dynamical centre of the Galaxy (Sgr A*) is located $\sim$0{\deg}.07 from the origin. We calculate new independent estimates of the North Galactic Pole (NGP)...

Astronomers are entering an era of {\mu}as-level astrometry utilizing the 5-decade-old IAU Galactic coordinate system that was only originally defined to $\sim$0{\deg}.1 accuracy, and where the dynamical centre of the Galaxy (Sgr A*) is located $\sim$0{\deg}.07 from the origin. We calculate new independent estimates of the North Galactic Pole (NGP)...

Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast, the angular momentum distributions of older T Tauri stars (4-10 Myr) have been less studied, even though they hold key insight to understanding stellar angular momentum evolution at a time when prot...

Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast, the angular momentum distributions of older T Tauri stars (4-10 Myr) have been less studied, even though they hold key insight to understanding stellar angular momentum evolution at a time when prot...

Most existing studies of young stellar populations have focused on the youngest (< 2-3 Myr) T-Tauri stars, which are usually associated with their natal gas and hence easier to identify. In contrast, older T-Tauri stars (~ 4-10 Myr), being more difficult to find, have been less studied, even though they hold key insight to understanding evolution o...